645995900 has 36 divisors (see below), whose sum is σ = 1529251080. Its totient is φ = 234907200.

The previous prime is 645995879. The next prime is 645995941. The reversal of 645995900 is 9599546.

It is a super-3 number, since 3×645995900³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 292535 + ... + 294734.

Almost surely, 2^645995900 is an apocalyptic number.

It is an amenable number.

645995900 is an abundant number, since it is smaller than the sum of its proper divisors (883255180).

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

645995900 is a wasteful number, since it uses less digits than its factorization.

645995900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587294 (or 587287 counting only the distinct ones).

The product of its (nonzero) digits is 437400, while the sum is 47.

The square root of 645995900 is about 25416.4493979785. The cubic root of 645995900 is about 864.4567183370.

The spelling of 645995900 in words is "six hundred forty-five million, nine hundred ninety-five thousand, nine hundred".