644449760960 has 28 divisors (see below), whose sum is σ = 1534595994048. Its totient is φ = 257779904256.

The previous prime is 644449760953. The next prime is 644449761019. The reversal of 644449760960 is 69067944446.

It is a happy number.

It is a super-2 number, since 2×644449760960² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644449760960.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1006952432 + ... + 1006953071.

Almost surely, 2^644449760960 is an apocalyptic number.

It is an amenable number.

644449760960 is an abundant number, since it is smaller than the sum of its proper divisors (890146233088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644449760960 is a wasteful number, since it uses less digits than its factorization.

644449760960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2013905520 (or 2013905510 counting only the distinct ones).

The product of its (nonzero) digits is 31352832, while the sum is 59.

The spelling of 644449760960 in words is "six hundred forty-four billion, four hundred forty-nine million, seven hundred sixty thousand, nine hundred sixty".