a primitive abundant number is an abundant number whose proper divisors are all deficient numbers. For example, 20 is a primitive abundant number because:...

quasiperfect number, although none have yet been found. Every abundant number is a multiple of either a perfect number or a primitive abundant number. Numbers...

score. Twenty is a composite number. It is also the smallest primitive abundant number. The Happy Family of sporadic groups is made up of twenty finite...

also the twentieth abundant and highly abundant number (with 20 the first primitive abundant number and 70 the second). The number of divisors of 90 is...

semiperfect number is 945. A semiperfect number is necessarily either perfect or abundant. An abundant number that is not semiperfect is called a weird number. With...

smallest weird number, a natural number that is abundant but not semiperfect, where it is also the second-smallest primitive abundant number, after 20. 70...

pyramidal number 1376 = primitive abundant number (abundant number all of whose proper divisors are deficient numbers) 1377 = maximal number of pieces...

primitive abundant number; smallest odd primitive semiperfect number; Leyland number 946 = 2 × 11 × 43, sphenic number, 43rd triangular number, hexagonal...

pentagonal pyramidal number. a primitive abundant number. a nontotient. a repdigit in bases 24 (MM24), 49 (BB49), and 54 (AA54). a Harshad number. the SMTP status...

the natural number following 599 and preceding 601. Six hundred is a composite number, an abundant number, a pronic number, a Harshad number and a largely...

{4^{23}}{3^{23}}}\right\rfloor } , palindromic number. 748 = 22 × 11 × 17, nontotient, happy number, primitive abundant number 749 = 7 × 107, sum of three consecutive...

In number theory, a weird number is a natural number that is abundant but not semiperfect. In other words, the sum of the proper divisors (divisors including...

after the baseball term 464 = 24 × 29, primitive abundant number, since 464 = 212 + 21 + 2 it is the maximum number of regions into which 22 intersecting...

In number theory, a highly abundant number is a natural number with the property that the sum of its divisors (including itself) is greater than the sum...

In number theory, a colossally abundant number (sometimes abbreviated as CA) is a natural number that, in a particular, rigorous sense, has many divisors...

m a primitive abundant number is an abundant number whose proper divisors are all deficient numbers a weird number is a number that is abundant but not...

natural number following 87 and preceding 89. 88 is: a refactorable number. a primitive semiperfect number. an untouchable number. a hexadecagonal number. an...

A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Accordingly it is a positive integer that has...

perfect number. Most abundant numbers are also semiperfect; abundant numbers which are not semiperfect are called weird numbers. Hyperperfect number Multiply...

recreational mathematics, a vampire number (or true vampire number) is a composite natural number with an even number of digits, that can be factored into...

natural number following 137 and preceding 139. 138 is a sphenic number, an Ulam number, an abundant number, and a square-free congruent number. Sloane...

the set of all practical numbers there is a primitive set of practical numbers. A primitive practical number is either practical and squarefree or practical...

In number theory, a happy number is a number which eventually reaches 1 when the number is replaced by the sum of the square of each digit. For instance...

month, the number of pairs of rabbits is equal to the number of mature pairs (that is, the number of pairs in month n – 2) plus the number of pairs alive...

triangular number or triangle number counts objects arranged in an equilateral triangle. Triangular numbers are a type of figurate number, other examples...

In number theory, an n-smooth (or n-friable) number is an integer whose prime factors are all less than or equal to n. For example, a 7-smooth number is...

A palindromic number (also known as a numeral palindrome or a numeric palindrome) is a number (such as 16361) that remains the same when its digits are...

they were previously discovered in the 1730s by Minggatu. The n-th Catalan number can be expressed directly in terms of the central binomial coefficients...

first 15 colossally abundant numbers, which meet a similar condition based on the sum-of-divisors function rather than the number of divisors. Neither...

counting and arranging numbered objects, such as partitions and enumerations. The most primitive method of representing a natural number is to use one's fingers...