640958 has 16 divisors (see below), whose sum is σ = 1021680. Its totient is φ = 301056.

The previous prime is 640957. The next prime is 640963. The reversal of 640958 is 859046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2366 + ... + 2622.

It is an arithmetic number, because the mean of its divisors is an integer number (63855).

2⁶⁴⁰⁹⁵⁸ is an apocalyptic number.

640958 is a deficient number, since it is larger than the sum of its proper divisors (380722).

640958 is a wasteful number, since it uses less digits than its factorization.

640958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 640958 is about 800.5985261041. The cubic root of 640958 is about 86.2203650901.

The spelling of 640958 in words is "six hundred forty thousand, nine hundred fifty-eight".