638491941184 has 28 divisors (see below), whose sum is σ = 1267034724244. Its totient is φ = 319239097344.

The previous prime is 638491941173. The next prime is 638491941221. The reversal of 638491941184 is 481149194836.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 543652579584 + 94839361600 = 737328^2 + 307960^2 .

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, 4274284 + ... + 4421140.

Almost surely, 2^638491941184 is an apocalyptic number.

638491941184 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

638491941184 is a deficient number, since it is larger than the sum of its proper divisors (628542783060).

638491941184 is a wasteful number, since it uses less digits than its factorization.

638491941184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214802 (or 214792 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 58.

The spelling of 638491941184 in words is "six hundred thirty-eight billion, four hundred ninety-one million, nine hundred forty-one thousand, one hundred eighty-four".