638915 has 8 divisors (see below), whose sum is σ = 781488. Its totient is φ = 501280.

The previous prime is 638893. The next prime is 638923. The reversal of 638915 is 519836.

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

It is not a de Polignac number, because 638915 - 2¹⁶ = 573379 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 941 + ... + 1470.

It is an arithmetic number, because the mean of its divisors is an integer number (97686).

2⁶³⁸⁹¹⁵ is an apocalyptic number.

638915 is a deficient number, since it is larger than the sum of its proper divisors (142573).

638915 is a wasteful number, since it uses less digits than its factorization.

638915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2469.

The product of its digits is 6480, while the sum is 32.

The square root of 638915 is about 799.3215873477. The cubic root of 638915 is about 86.1286608544.

The spelling of 638915 in words is "six hundred thirty-eight thousand, nine hundred fifteen".