644646730675 has 24 divisors (see below), whose sum is σ = 834389140320. Its totient is φ = 493133836800.

The previous prime is 644646730649. The next prime is 644646730687. The reversal of 644646730675 is 576037646446.

It is not a de Polignac number, because 644646730675 - 2¹⁷ = 644646599603 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1594705 + ... + 1957645.

It is an arithmetic number, because the mean of its divisors is an integer number (34766214180).

Almost surely, 2^644646730675 is an apocalyptic number.

644646730675 is a deficient number, since it is larger than the sum of its proper divisors (189742409645).

644646730675 is a wasteful number, since it uses less digits than its factorization.

644646730675 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366063 (or 366058 counting only the distinct ones).

The product of its (nonzero) digits is 60963840, while the sum is 58.

The spelling of 644646730675 in words is "six hundred forty-four billion, six hundred forty-six million, seven hundred thirty thousand, six hundred seventy-five".