21512343504 has 20 divisors (see below), whose sum is σ = 55573554176. Its totient is φ = 7170781152.

The previous prime is 21512343497. The next prime is 21512343563. The reversal of 21512343504 is 40534321512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224086864 + ... + 224086959.

Almost surely, 2^21512343504 is an apocalyptic number.

21512343504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21512343504 is an abundant number, since it is smaller than the sum of its proper divisors (34061210672).

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

21512343504 is a wasteful number, since it uses less digits than its factorization.

21512343504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448173834 (or 448173828 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

The spelling of 21512343504 in words is "twenty-one billion, five hundred twelve million, three hundred forty-three thousand, five hundred four".