638613622881 has 80 divisors (see below), whose sum is σ = 1040643172800. Its totient is φ = 387945106560.

The previous prime is 638613622853. The next prime is 638613622903. The reversal of 638613622881 is 188226316836.

638613622881 is a `hidden beast` number, since 6 + 3 + 8 + 6 + 1 + 3 + 622 + 8 + 8 + 1 = 666.

It is not a de Polignac number, because 638613622881 - 2⁷ = 638613622753 is a prime.

It is a super-2 number, since 2×638613622881² (a number of 24 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (638613622081) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 25561726 + ... + 25586696.

It is an arithmetic number, because the mean of its divisors is an integer number (13008039660).

Almost surely, 2^638613622881 is an apocalyptic number.

It is an amenable number.

638613622881 is a deficient number, since it is larger than the sum of its proper divisors (402029549919).

638613622881 is a wasteful number, since it uses less digits than its factorization.

638613622881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25308 (or 25299 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 54.

The spelling of 638613622881 in words is "six hundred thirty-eight billion, six hundred thirteen million, six hundred twenty-two thousand, eight hundred eighty-one".