638965 has 8 divisors (see below), whose sum is σ = 783360. Its totient is φ = 500112.

The previous prime is 638959. The next prime is 638971. The reversal of 638965 is 569836.

It is an interprime number because it is at equal distance from previous prime (638959) and next prime (638971).

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

It is a cyclic number.

It is not a de Polignac number, because 638965 - 2⁵ = 638933 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1125 + ... + 1594.

It is an arithmetic number, because the mean of its divisors is an integer number (97920).

2⁶³⁸⁹⁶⁵ is an apocalyptic number.

It is an amenable number.

638965 is a deficient number, since it is larger than the sum of its proper divisors (144395).

638965 is a wasteful number, since it uses less digits than its factorization.

638965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2771.

The product of its digits is 38880, while the sum is 37.

The square root of 638965 is about 799.3528632588. The cubic root of 638965 is about 86.1309075386.

The spelling of 638965 in words is "six hundred thirty-eight thousand, nine hundred sixty-five".