638580885681 has 24 divisors (see below), whose sum is σ = 898947798240. Its totient is φ = 403163728704.

The previous prime is 638580885671. The next prime is 638580885773. The reversal of 638580885681 is 186588085836.

It is not a de Polignac number, because 638580885681 - 2⁹ = 638580885169 is a prime.

It is a super-2 number, since 2×638580885681² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (638580885661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2829510 + ... + 3046848.

It is an arithmetic number, because the mean of its divisors is an integer number (37456158260).

Almost surely, 2^638580885681 is an apocalyptic number.

It is an amenable number.

638580885681 is a deficient number, since it is larger than the sum of its proper divisors (260366912559).

638580885681 is a wasteful number, since it uses less digits than its factorization.

638580885681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220093 (or 220074 counting only the distinct ones).

The product of its (nonzero) digits is 88473600, while the sum is 66.

The spelling of 638580885681 in words is "six hundred thirty-eight billion, five hundred eighty million, eight hundred eighty-five thousand, six hundred eighty-one".