644918965594 has 16 divisors (see below), whose sum is σ = 980800830720. Its totient is φ = 317986892640.

The previous prime is 644918965583. The next prime is 644918965619. The reversal of 644918965594 is 495569819446.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 464097 + ... + 1226875.

It is an arithmetic number, because the mean of its divisors is an integer number (61300051920).

Almost surely, 2^644918965594 is an apocalyptic number.

644918965594 is a deficient number, since it is larger than the sum of its proper divisors (335881865126).

644918965594 is a wasteful number, since it uses less digits than its factorization.

644918965594 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768645.

The product of its digits is 335923200, while the sum is 70.

The spelling of 644918965594 in words is "six hundred forty-four billion, nine hundred eighteen million, nine hundred sixty-five thousand, five hundred ninety-four".