638605156690 has 16 divisors (see below), whose sum is σ = 1149832780992. Its totient is φ = 255365729584.

The previous prime is 638605156687. The next prime is 638605156729. The reversal of 638605156690 is 96651506836.

638605156690 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×638605156690² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9506494 + ... + 9573433.

It is an arithmetic number, because the mean of its divisors is an integer number (71864548812).

Almost surely, 2^638605156690 is an apocalyptic number.

638605156690 is a deficient number, since it is larger than the sum of its proper divisors (511227624302).

638605156690 is a wasteful number, since it uses less digits than its factorization.

638605156690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19083281.

The product of its (nonzero) digits is 6998400, while the sum is 55.

The spelling of 638605156690 in words is "six hundred thirty-eight billion, six hundred five million, one hundred fifty-six thousand, six hundred ninety".