638958965 has 8 divisors (see below), whose sum is σ = 785452248. Its totient is φ = 498699520.

The previous prime is 638958959. The next prime is 638958989. The reversal of 638958965 is 569859836.

It can be written as a sum of positive squares in 4 ways, for example, as 790321 + 638168644 = 889^2 + 25262^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638958965 - 2⁸ = 638958709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1558232 + ... + 1558641.

It is an arithmetic number, because the mean of its divisors is an integer number (98181531).

Almost surely, 2^638958965 is an apocalyptic number.

It is an amenable number.

638958965 is a deficient number, since it is larger than the sum of its proper divisors (146493283).

638958965 is a wasteful number, since it uses less digits than its factorization.

638958965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3116919.

The product of its digits is 13996800, while the sum is 59.

The square root of 638958965 is about 25277.6376467422. The cubic root of 638958965 is about 861.3063637004.

The spelling of 638958965 in words is "six hundred thirty-eight million, nine hundred fifty-eight thousand, nine hundred sixty-five".