644045540396 has 24 divisors (see below), whose sum is σ = 1193403047760. Its totient is φ = 303074020352.

The previous prime is 644045540389. The next prime is 644045540407. The reversal of 644045540396 is 693045540446.

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, 6295220 + ... + 6396708.

It is an arithmetic number, because the mean of its divisors is an integer number (49725126990).

Almost surely, 2^644045540396 is an apocalyptic number.

It is an amenable number.

644045540396 is a deficient number, since it is larger than the sum of its proper divisors (549357507364).

644045540396 is a wasteful number, since it uses less digits than its factorization.

644045540396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194833 (or 194831 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 50.

Adding to 644045540396 its sum of digits (50), we get a palindrome (644045540446).

The spelling of 644045540396 in words is "six hundred forty-four billion, forty-five million, five hundred forty thousand, three hundred ninety-six".