638494231 has 2 divisors, whose sum is σ = 638494232. Its totient is φ = 638494230.

The previous prime is 638494223. The next prime is 638494243. The reversal of 638494231 is 132494836.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638494231 - 2³ = 638494223 is a prime.

It is a super-2 number, since 2×638494231² = 815349766040562722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638494291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319247115 + 319247116.

It is an arithmetic number, because the mean of its divisors is an integer number (319247116).

Almost surely, 2^638494231 is an apocalyptic number.

638494231 is a deficient number, since it is larger than the sum of its proper divisors (1).

638494231 is an equidigital number, since it uses as much as digits as its factorization.

638494231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 40.

The square root of 638494231 is about 25268.4433830024. The cubic root of 638494231 is about 861.0974950783.

The spelling of 638494231 in words is "six hundred thirty-eight million, four hundred ninety-four thousand, two hundred thirty-one".