638713766 has 32 divisors (see below), whose sum is σ = 1078932960. Its totient is φ = 281788416.

The previous prime is 638713727. The next prime is 638713793. The reversal of 638713766 is 667317836.

It is a self number, because there is not a number n which added to its sum of digits gives 638713766.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 57566 + ... + 67758.

It is an arithmetic number, because the mean of its divisors is an integer number (33716655).

Almost surely, 2^638713766 is an apocalyptic number.

638713766 is a deficient number, since it is larger than the sum of its proper divisors (440219194).

638713766 is a wasteful number, since it uses less digits than its factorization.

638713766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10328.

The product of its digits is 762048, while the sum is 47.

The square root of 638713766 is about 25272.7870643505. The cubic root of 638713766 is about 861.1961748405.

The spelling of 638713766 in words is "six hundred thirty-eight million, seven hundred thirteen thousand, seven hundred sixty-six".