638806659 has 4 divisors (see below), whose sum is σ = 851742216. Its totient is φ = 425871104.

The previous prime is 638806643. The next prime is 638806673. The reversal of 638806659 is 956608836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638806659 - 2⁴ = 638806643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638806639) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 106467774 + ... + 106467779.

It is an arithmetic number, because the mean of its divisors is an integer number (212935554).

Almost surely, 2^638806659 is an apocalyptic number.

638806659 is a deficient number, since it is larger than the sum of its proper divisors (212935557).

638806659 is a wasteful number, since it uses less digits than its factorization.

638806659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212935556.

The product of its (nonzero) digits is 1866240, while the sum is 51.

The square root of 638806659 is about 25274.6248043369. The cubic root of 638806659 is about 861.2379229195.

The spelling of 638806659 in words is "six hundred thirty-eight million, eight hundred six thousand, six hundred fifty-nine".