21655012631 has 8 divisors (see below), whose sum is σ = 24753277824. Its totient is φ = 18557920440.

The previous prime is 21655012609. The next prime is 21655012651. The reversal of 21655012631 is 13621055612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21655012631 - 2²² = 21650818327 is a prime.

It is a super-2 number, since 2×21655012631² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21655012651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 253325 + ... + 327846.

It is an arithmetic number, because the mean of its divisors is an integer number (3094159728).

Almost surely, 2^21655012631 is an apocalyptic number.

21655012631 is a deficient number, since it is larger than the sum of its proper divisors (3098265193).

21655012631 is an equidigital number, since it uses as much as digits as its factorization.

21655012631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586501.

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21655012631 in words is "twenty-one billion, six hundred fifty-five million, twelve thousand, six hundred thirty-one".