645844521616 has 40 divisors (see below), whose sum is σ = 1492261881984. Its totient is φ = 264756138240.

The previous prime is 645844521559. The next prime is 645844521661. The reversal of 645844521616 is 616125448546.

It is a super-2 number, since 2×645844521616² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125355445 + ... + 125360596.

Almost surely, 2^645844521616 is an apocalyptic number.

It is an amenable number.

645844521616 is an abundant number, since it is smaller than the sum of its proper divisors (846417360368).

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

645844521616 is a wasteful number, since it uses less digits than its factorization.

645844521616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250716079 (or 250716073 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 52.

The spelling of 645844521616 in words is "six hundred forty-five billion, eight hundred forty-four million, five hundred twenty-one thousand, six hundred sixteen".