In mathematics a polydivisible number (or magic number) is a number in a given number base with digits abcde... that has the following properties: Its...

triacontagonal number 1018 = Mertens function zero, 101816 + 1 is prime 1019 = Sophie Germain prime, safe prime, Chen prime 1020 = polydivisible number 1021 =...

10 polydivisible number, since 1 is divisible by 1, 10 is divisible by 2 and 102 is divisible by 3. This also shows that 102 is a Harshad number. 102...

Mathematics: 3,608,528,850,368,400,786,036,725 (≈3.6×1024) is the largest polydivisible number. Mathematics – Impossiball: There are 23,563,902,142,421,896,679...

Practical number Juggler sequence Look-and-say sequence Polydivisible number Automorphic number Armstrong number Self number Harshad number Keith number Kaprekar...

superior highly composite number 380,204,032 = 525 381,654,729 = the only polydivisible number that is also a zeroless pandigital number 387,420,489 = 196832...

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...

A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that...

In number theory, a congruent number is a positive integer that is the area of a right triangle with three rational number sides. A more general definition...

number with the digits in order. 3816547290 = The polydivisible pandigital number; the only pandigital number where the first n digits are divisible by n....

In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so...

In number theory, a practical number or panarithmic number is a positive integer n {\displaystyle n} such that all smaller positive integers can be represented...

A pronic number is a number that is the product of two consecutive integers, that is, a number of the form n ( n + 1 ) {\displaystyle n(n+1)} . The study...

highly composite number is a positive integer that has more divisors than all smaller positive integers. If d(n) denotes the number of divisors of a positive...

In mathematics, an automorphic number (sometimes referred to as a circular number) is a natural number in a given number base b {\displaystyle b} whose...

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...

In number theory, a perfect number is a positive integer that is equal to the sum of its positive proper divisors, that is, divisors excluding the number...

In number theory, a Carmichael number is a composite number ⁠ n {\displaystyle n} ⁠ which in modular arithmetic satisfies the congruence relation: b n...

mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form Mn = 2n − 1 for some integer...

In number theory, a polite number is a positive integer that can be written as the sum of two or more consecutive positive integers. A positive integer...

the number 1 differently than larger numbers, sometimes even not as a number at all. Euclid, for example, defined a unit first and then a number as a...

In number theory, a Thabit number, Thâbit ibn Qurra number, or 321 number is an integer of the form 3 ⋅ 2 n − 1 {\displaystyle 3\cdot 2^{n}-1} for a non-negative...

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...

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...

algebra, the cube of a number n is its third power, that is, the result of multiplying three instances of n together. The cube of a number n is denoted n3,...

starts with 0 and 1, then each following number is found by adding the number before it to twice the number before that. The first Jacobsthal numbers...

A pentagonal number is a figurate number that extends the concept of triangular and square numbers to the pentagon, but, unlike the first two, the patterns...

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...

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, a pentatope number is a number in the fifth cell of any row of Pascal's triangle starting with the 5-term row 1 4 6 4 1, either from...