21815057712 has 80 divisors (see below), whose sum is σ = 65130117120. Its totient is φ = 6162832896.

The previous prime is 21815057707. The next prime is 21815057729. The reversal of 21815057712 is 21775051812.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 334848 + ... + 394655.

It is an arithmetic number, because the mean of its divisors is an integer number (814126464).

Almost surely, 2^21815057712 is an apocalyptic number.

It is an amenable number.

21815057712 is an abundant number, since it is smaller than the sum of its proper divisors (43315059408).

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

21815057712 is a wasteful number, since it uses less digits than its factorization.

21815057712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729610 (or 729604 counting only the distinct ones).

The product of its (nonzero) digits is 39200, while the sum is 39.

The spelling of 21815057712 in words is "twenty-one billion, eight hundred fifteen million, fifty-seven thousand, seven hundred twelve".