638679 has 8 divisors (see below), whose sum is σ = 871552. Its totient is φ = 415800.

The previous prime is 638669. The next prime is 638689. The reversal of 638679 is 976836.

It is an interprime number because it is at equal distance from previous prime (638669) and next prime (638689).

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

It is not a de Polignac number, because 638679 - 2⁴ = 638663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2347 + ... + 2604.

It is an arithmetic number, because the mean of its divisors is an integer number (108944).

2⁶³⁸⁶⁷⁹ is an apocalyptic number.

638679 is a deficient number, since it is larger than the sum of its proper divisors (232873).

638679 is a wasteful number, since it uses less digits than its factorization.

638679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4997.

The product of its digits is 54432, while the sum is 39.

The square root of 638679 is about 799.1739485243. The cubic root of 638679 is about 86.1180549224.

The spelling of 638679 in words is "six hundred thirty-eight thousand, six hundred seventy-nine".