638865423 has 36 divisors (see below), whose sum is σ = 1120353520. Its totient is φ = 343581696.

The previous prime is 638865419. The next prime is 638865433. The reversal of 638865423 is 324568836.

It is a happy number.

638865423 is a `hidden beast` number, since 638 + 8 + 6 + 5 + 4 + 2 + 3 = 666.

It is not a de Polignac number, because 638865423 - 2² = 638865419 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 (638865433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 663 + ... + 35751.

Almost surely, 2^638865423 is an apocalyptic number.

638865423 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

638865423 is a deficient number, since it is larger than the sum of its proper divisors (481488097).

638865423 is a wasteful number, since it uses less digits than its factorization.

638865423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35136 (or 35116 counting only the distinct ones).

The product of its digits is 829440, while the sum is 45.

The square root of 638865423 is about 25275.7872874417. The cubic root of 638865423 is about 861.2643306141.

The spelling of 638865423 in words is "six hundred thirty-eight million, eight hundred sixty-five thousand, four hundred twenty-three".