639475 has 6 divisors (see below), whose sum is σ = 792980. Its totient is φ = 511560.

The previous prime is 639451. The next prime is 639487. The reversal of 639475 is 574936.

It is a de Polignac number, because none of the positive numbers 2^k-639475 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639475.

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 5 ways as a sum of consecutive naturals, for example, 12765 + ... + 12814.

2⁶³⁹⁴⁷⁵ is an apocalyptic number.

639475 is a deficient number, since it is larger than the sum of its proper divisors (153505).

639475 is a wasteful number, since it uses less digits than its factorization.

639475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25589 (or 25584 counting only the distinct ones).

The product of its digits is 22680, while the sum is 34.

The square root of 639475 is about 799.6718076811. The cubic root of 639475 is about 86.1538170256.

The spelling of 639475 in words is "six hundred thirty-nine thousand, four hundred seventy-five".