645260640644 has 12 divisors (see below), whose sum is σ = 1129239417600. Its totient is φ = 322620807048.

The previous prime is 645260640611. The next prime is 645260640679. The reversal of 645260640644 is 446046062546.

It is a super-2 number, since 2×645260640644² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2224604 + ... + 2497875.

It is an arithmetic number, because the mean of its divisors is an integer number (94103284800).

Almost surely, 2^645260640644 is an apocalyptic number.

It is an amenable number.

645260640644 is a deficient number, since it is larger than the sum of its proper divisors (483978776956).

645260640644 is a wasteful number, since it uses less digits than its factorization.

645260640644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4756642 (or 4756640 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 47.

The spelling of 645260640644 in words is "six hundred forty-five billion, two hundred sixty million, six hundred forty thousand, six hundred forty-four".