645957860 has 12 divisors (see below), whose sum is σ = 1356511548. Its totient is φ = 258383136.

The previous prime is 645957821. The next prime is 645957863. The reversal of 645957860 is 68759546.

It can be written as a sum of positive squares in 2 ways, for example, as 506340004 + 139617856 = 22502^2 + 11816^2 .

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 645957799 and 645957808.

It is not an unprimeable number, because it can be changed into a prime (645957863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16148927 + ... + 16148966.

It is an arithmetic number, because the mean of its divisors is an integer number (113042629).

Almost surely, 2^645957860 is an apocalyptic number.

It is an amenable number.

645957860 is an abundant number, since it is smaller than the sum of its proper divisors (710553688).

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

645957860 is a wasteful number, since it uses less digits than its factorization.

645957860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32297902 (or 32297900 counting only the distinct ones).

The product of its (nonzero) digits is 1814400, while the sum is 50.

The square root of 645957860 is about 25415.7010526958. The cubic root of 645957860 is about 864.4397499223.

The spelling of 645957860 in words is "six hundred forty-five million, nine hundred fifty-seven thousand, eight hundred sixty".