638166120628 has 12 divisors (see below), whose sum is σ = 1116920284480. Its totient is φ = 319046039352.

The previous prime is 638166120607. The next prime is 638166120661. The reversal of 638166120628 is 826021661836.

It is a happy number.

It is a super-2 number, since 2×638166120628² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9216438 + ... + 9285421.

Almost surely, 2^638166120628 is an apocalyptic number.

It is an amenable number.

638166120628 is a deficient number, since it is larger than the sum of its proper divisors (478754163852).

638166120628 is a wasteful number, since it uses less digits than its factorization.

638166120628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18510486 (or 18510484 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 49.

The spelling of 638166120628 in words is "six hundred thirty-eight billion, one hundred sixty-six million, one hundred twenty thousand, six hundred twenty-eight".