21631515087 has 64 divisors (see below), whose sum is σ = 35804160000. Its totient is φ = 11312016768.

The previous prime is 21631515083. The next prime is 21631515097. The reversal of 21631515087 is 78051513612.

It is not a de Polignac number, because 21631515087 - 2² = 21631515083 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21631515083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 29270964 + ... + 29271702.

It is an arithmetic number, because the mean of its divisors is an integer number (559440000).

Almost surely, 2^21631515087 is an apocalyptic number.

21631515087 is a deficient number, since it is larger than the sum of its proper divisors (14172644913).

21631515087 is a wasteful number, since it uses less digits than its factorization.

21631515087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540.

The product of its (nonzero) digits is 50400, while the sum is 39.

The spelling of 21631515087 in words is "twenty-one billion, six hundred thirty-one million, five hundred fifteen thousand, eighty-seven".