638820330831 has 20 divisors (see below), whose sum is σ = 954311878872. Its totient is φ = 425869189488.

The previous prime is 638820330773. The next prime is 638820330961. The reversal of 638820330831 is 138033028836.

638820330831 is a `hidden beast` number, since 6 + 388 + 203 + 30 + 8 + 31 = 666.

It is not a de Polignac number, because 638820330831 - 2³⁷ = 501381377359 is a prime.

It is a super-2 number, since 2×638820330831² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638860330831) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4110025 + ... + 4262621.

Almost surely, 2^638820330831 is an apocalyptic number.

638820330831 is a deficient number, since it is larger than the sum of its proper divisors (315491548041).

638820330831 is a wasteful number, since it uses less digits than its factorization.

638820330831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204292 (or 204283 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 638820330831 in words is "six hundred thirty-eight billion, eight hundred twenty million, three hundred thirty thousand, eight hundred thirty-one".