645017515944 has 16 divisors (see below), whose sum is σ = 1612543789920. Its totient is φ = 215005838640.

The previous prime is 645017515931. The next prime is 645017515993. The reversal of 645017515944 is 449515710546.

It is a happy number.

It is a super-2 number, since 2×645017515944² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13437864892 + ... + 13437864939.

It is an arithmetic number, because the mean of its divisors is an integer number (100783986870).

Almost surely, 2^645017515944 is an apocalyptic number.

It is an amenable number.

645017515944 is an abundant number, since it is smaller than the sum of its proper divisors (967526273976).

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

645017515944 is a wasteful number, since it uses less digits than its factorization.

645017515944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26875729840 (or 26875729836 counting only the distinct ones).

The product of its (nonzero) digits is 3024000, while the sum is 51.

The spelling of 645017515944 in words is "six hundred forty-five billion, seventeen million, five hundred fifteen thousand, nine hundred forty-four".