638643315 has 8 divisors (see below), whose sum is σ = 1021829328. Its totient is φ = 340609760.

The previous prime is 638643293. The next prime is 638643319. The reversal of 638643315 is 513346836.

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

It is not a de Polignac number, because 638643315 - 2⁵ = 638643283 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638643319) 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, 21288096 + ... + 21288125.

It is an arithmetic number, because the mean of its divisors is an integer number (127728666).

Almost surely, 2^638643315 is an apocalyptic number.

638643315 is a deficient number, since it is larger than the sum of its proper divisors (383186013).

638643315 is a wasteful number, since it uses less digits than its factorization.

638643315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42576229.

The product of its digits is 155520, while the sum is 39.

The square root of 638643315 is about 25271.3932144629. The cubic root of 638643315 is about 861.1645099718.

The spelling of 638643315 in words is "six hundred thirty-eight million, six hundred forty-three thousand, three hundred fifteen".