638633788 has 24 divisors (see below), whose sum is σ = 1218822080. Its totient is φ = 291021120.

The previous prime is 638633773. The next prime is 638633797. The reversal of 638633788 is 887336836.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73623 + ... + 81838.

Almost surely, 2^638633788 is an apocalyptic number.

It is an amenable number.

638633788 is a deficient number, since it is larger than the sum of its proper divisors (580188292).

638633788 is a wasteful number, since it uses less digits than its factorization.

638633788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155557 (or 155555 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 52.

The square root of 638633788 is about 25271.2047199970. The cubic root of 638633788 is about 861.1602277928.

The spelling of 638633788 in words is "six hundred thirty-eight million, six hundred thirty-three thousand, seven hundred eighty-eight".