21657475712 has 16 divisors (see below), whose sum is σ = 43145752650. Its totient is φ = 10828737792.

The previous prime is 21657475691. The next prime is 21657475727. The reversal of 21657475712 is 21757475612.

It can be written as a sum of positive squares in only one way, i.e., 21613704256 + 43771456 = 147016^2 + 6616^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84599387 + ... + 84599642.

Almost surely, 2^21657475712 is an apocalyptic number.

It is an amenable number.

21657475712 is a deficient number, since it is larger than the sum of its proper divisors (21488276938).

21657475712 is an equidigital number, since it uses as much as digits as its factorization.

21657475712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169199043 (or 169199031 counting only the distinct ones).

The product of its digits is 823200, while the sum is 47.

The spelling of 21657475712 in words is "twenty-one billion, six hundred fifty-seven million, four hundred seventy-five thousand, seven hundred twelve".