646441645636 has 24 divisors (see below), whose sum is σ = 1165559879960. Its totient is φ = 313480357632.

The previous prime is 646441645631. The next prime is 646441645693. The reversal of 646441645636 is 636546144646.

It can be written as a sum of positive squares in 4 ways, for example, as 437228100 + 646004417536 = 20910^2 + 803744^2 .

It is not an unprimeable number, because it can be changed into a prime (646441645631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6931071 + ... + 7023718.

Almost surely, 2^646441645636 is an apocalyptic number.

It is an amenable number.

646441645636 is a deficient number, since it is larger than the sum of its proper divisors (519118234324).

646441645636 is a wasteful number, since it uses less digits than its factorization.

646441645636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13955143 (or 13955141 counting only the distinct ones).

The product of its digits is 29859840, while the sum is 55.

The spelling of 646441645636 in words is "six hundred forty-six billion, four hundred forty-one million, six hundred forty-five thousand, six hundred thirty-six".