645389502816 has 48 divisors (see below), whose sum is σ = 1694262924144. Its totient is φ = 215115170304.

The previous prime is 645389502781. The next prime is 645389502839. The reversal of 645389502816 is 618205983546.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×645389502816² (a number of 24 digits) contains 22 as substring.

It is a congruent 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, 1235070 + ... + 1678146.

It is an arithmetic number, because the mean of its divisors is an integer number (35297144253).

Almost surely, 2^645389502816 is an apocalyptic number.

It is an amenable number.

645389502816 is an abundant number, since it is smaller than the sum of its proper divisors (1048873421328).

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

645389502816 is a wasteful number, since it uses less digits than its factorization.

645389502816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458263 (or 458255 counting only the distinct ones).

The product of its (nonzero) digits is 12441600, while the sum is 57.

The spelling of 645389502816 in words is "six hundred forty-five billion, three hundred eighty-nine million, five hundred two thousand, eight hundred sixteen".