21705520364 has 12 divisors (see below), whose sum is σ = 41437811688. Its totient is φ = 9866145600.

The previous prime is 21705520357. The next prime is 21705520451. The reversal of 21705520364 is 46302550712.

It is a super-2 number, since 2×21705520364² (a number of 21 digits) contains 22 as substring.

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, 246653597 + ... + 246653684.

It is an arithmetic number, because the mean of its divisors is an integer number (3453150974).

Almost surely, 2^21705520364 is an apocalyptic number.

It is an amenable number.

21705520364 is a deficient number, since it is larger than the sum of its proper divisors (19732291324).

21705520364 is a wasteful number, since it uses less digits than its factorization.

21705520364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493307296 (or 493307294 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 35.

The spelling of 21705520364 in words is "twenty-one billion, seven hundred five million, five hundred twenty thousand, three hundred sixty-four".