638612644 has 12 divisors (see below), whose sum is σ = 1134252784. Its totient is φ = 314540424.

The previous prime is 638612627. The next prime is 638612657. The reversal of 638612644 is 446216836.

It is a super-2 number, since 2×638612644² = 815652218153341472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 638612597 and 638612606.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1191174 + ... + 1191709.

Almost surely, 2^638612644 is an apocalyptic number.

It is an amenable number.

638612644 is a deficient number, since it is larger than the sum of its proper divisors (495640140).

638612644 is a wasteful number, since it uses less digits than its factorization.

638612644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2382954 (or 2382952 counting only the distinct ones).

The product of its digits is 165888, while the sum is 40.

The square root of 638612644 is about 25270.7863747846. The cubic root of 638612644 is about 861.1507238730.

The spelling of 638612644 in words is "six hundred thirty-eight million, six hundred twelve thousand, six hundred forty-four".