638851397 has 8 divisors (see below), whose sum is σ = 656729280. Its totient is φ = 621220320.

The previous prime is 638851391. The next prime is 638851399. The reversal of 638851397 is 793158836.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 638851397 - 2⁶ = 638851333 is a prime.

It is a super-2 number, since 2×638851397² = 816262214897703218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638851391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56447 + ... + 66812.

It is an arithmetic number, because the mean of its divisors is an integer number (82091160).

Almost surely, 2^638851397 is an apocalyptic number.

It is an amenable number.

638851397 is a deficient number, since it is larger than the sum of its proper divisors (17877883).

638851397 is a wasteful number, since it uses less digits than its factorization.

638851397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123403.

The product of its digits is 1088640, while the sum is 50.

The square root of 638851397 is about 25275.5098267077. The cubic root of 638851397 is about 861.2580276790.

The spelling of 638851397 in words is "six hundred thirty-eight million, eight hundred fifty-one thousand, three hundred ninety-seven".