638466687 has 48 divisors (see below), whose sum is σ = 966232800. Its totient is φ = 406010880.

The previous prime is 638466679. The next prime is 638466721. The reversal of 638466687 is 786664836.

It is not a de Polignac number, because 638466687 - 2³ = 638466679 is a prime.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638466677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3566764 + ... + 3566942.

It is an arithmetic number, because the mean of its divisors is an integer number (20129850).

Almost surely, 2^638466687 is an apocalyptic number.

638466687 is a deficient number, since it is larger than the sum of its proper divisors (327766113).

638466687 is a wasteful number, since it uses less digits than its factorization.

638466687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408 (or 405 counting only the distinct ones).

The product of its digits is 6967296, while the sum is 54.

The square root of 638466687 is about 25267.8983494868. The cubic root of 638466687 is about 861.0851126065.

The spelling of 638466687 in words is "six hundred thirty-eight million, four hundred sixty-six thousand, six hundred eighty-seven".