6645438656 has 14 divisors (see below), whose sum is σ = 13187042460. Its totient is φ = 3322719296.

The previous prime is 6645438607. The next prime is 6645438671. The reversal of 6645438656 is 6568345466.

It is a junction number, because it is equal to n+sod(n) for n = 6645438598 and 6645438607.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51917426 + ... + 51917553.

Almost surely, 2^6645438656 is an apocalyptic number.

It is an amenable number.

6645438656 is a deficient number, since it is larger than the sum of its proper divisors (6541603804).

6645438656 is a wasteful number, since it uses less digits than its factorization.

6645438656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103834991 (or 103834981 counting only the distinct ones).

The product of its digits is 12441600, while the sum is 53.

The square root of 6645438656 is about 81519.5599595582. The cubic root of 6645438656 is about 1880.0723014294.

The spelling of 6645438656 in words is "six billion, six hundred forty-five million, four hundred thirty-eight thousand, six hundred fifty-six".