21312613500 has 96 divisors (see below), whose sum is σ = 65328856320. Its totient is φ = 5384232000.

The previous prime is 21312613493. The next prime is 21312613501. The reversal of 21312613500 is 531621312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312613501) 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 31 ways as a sum of consecutive naturals, for example, 345406 + ... + 402405.

It is an arithmetic number, because the mean of its divisors is an integer number (680508920).

Almost surely, 2^21312613500 is an apocalyptic number.

21312613500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21312613500 is an abundant number, since it is smaller than the sum of its proper divisors (44016242820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21312613500 is a wasteful number, since it uses less digits than its factorization.

21312613500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 747852 (or 747840 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The spelling of 21312613500 in words is "twenty-one billion, three hundred twelve million, six hundred thirteen thousand, five hundred".