645964 has 24 divisors (see below), whose sum is σ = 1261008. Its totient is φ = 287040.

The previous prime is 645941. The next prime is 645973. The reversal of 645964 is 469546.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2194 + ... + 2470.

It is an arithmetic number, because the mean of its divisors is an integer number (52542).

2⁶⁴⁵⁹⁶⁴ is an apocalyptic number.

It is an amenable number.

645964 is a deficient number, since it is larger than the sum of its proper divisors (615044).

645964 is a wasteful number, since it uses less digits than its factorization.

645964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345 (or 343 counting only the distinct ones).

The product of its digits is 25920, while the sum is 34.

The square root of 645964 is about 803.7188563173. The cubic root of 645964 is about 86.4442488823. Note that the first 3 decimals are identical.

The spelling of 645964 in words is "six hundred forty-five thousand, nine hundred sixty-four".