645620860 has 12 divisors (see below), whose sum is σ = 1355803848. Its totient is φ = 258248336.

The previous prime is 645620839. The next prime is 645620897. The reversal of 645620860 is 68026546.

It is a congruent number.

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, 16140502 + ... + 16140541.

It is an arithmetic number, because the mean of its divisors is an integer number (112983654).

Almost surely, 2^645620860 is an apocalyptic number.

It is an amenable number.

645620860 is an abundant number, since it is smaller than the sum of its proper divisors (710182988).

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

645620860 is a wasteful number, since it uses less digits than its factorization.

645620860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32281052 (or 32281050 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 37.

The square root of 645620860 is about 25409.0704277036. The cubic root of 645620860 is about 864.2893960118.

The spelling of 645620860 in words is "six hundred forty-five million, six hundred twenty thousand, eight hundred sixty".