638669801 has 8 divisors (see below), whose sum is σ = 796263744. Its totient is φ = 497664720.

The previous prime is 638669791. The next prime is 638669831. The reversal of 638669801 is 108966836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638669801 - 2²² = 634475497 is a prime.

It is a super-2 number, since 2×638669801² = 815798229418759202, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638669831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4147130 + ... + 4147283.

It is an arithmetic number, because the mean of its divisors is an integer number (99532968).

Almost surely, 2^638669801 is an apocalyptic number.

It is an amenable number.

638669801 is a deficient number, since it is larger than the sum of its proper divisors (157593943).

638669801 is a wasteful number, since it uses less digits than its factorization.

638669801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8294431.

The product of its (nonzero) digits is 373248, while the sum is 47.

The square root of 638669801 is about 25271.9172402887. The cubic root of 638669801 is about 861.1764146283.

The spelling of 638669801 in words is "six hundred thirty-eight million, six hundred sixty-nine thousand, eight hundred one".