638765371 has 4 divisors (see below), whose sum is σ = 645942600. Its totient is φ = 631588144.

The previous prime is 638765359. The next prime is 638765399. The reversal of 638765371 is 173567836.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 638765371 - 2⁹ = 638764859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638765321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3588481 + ... + 3588658.

It is an arithmetic number, because the mean of its divisors is an integer number (161485650).

Almost surely, 2^638765371 is an apocalyptic number.

638765371 is a deficient number, since it is larger than the sum of its proper divisors (7177229).

638765371 is an equidigital number, since it uses as much as digits as its factorization.

638765371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7177228.

The product of its digits is 635040, while the sum is 46.

The square root of 638765371 is about 25273.8080035439. The cubic root of 638765371 is about 861.2193677187.

The spelling of 638765371 in words is "six hundred thirty-eight million, seven hundred sixty-five thousand, three hundred seventy-one".