638633331 has 24 divisors (see below), whose sum is σ = 1090608480. Its totient is φ = 352348416.

The previous prime is 638633329. The next prime is 638633351. The reversal of 638633331 is 133336836.

It is not a de Polignac number, because 638633331 - 2¹ = 638633329 is a prime.

It is a super-2 number, since 2×638633331² = 815705062928311122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (638633351) 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 23 ways as a sum of consecutive naturals, for example, 172950 + ... + 176603.

It is an arithmetic number, because the mean of its divisors is an integer number (45442020).

Almost surely, 2^638633331 is an apocalyptic number.

638633331 is a deficient number, since it is larger than the sum of its proper divisors (451975149).

638633331 is a wasteful number, since it uses less digits than its factorization.

638633331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349595 (or 349592 counting only the distinct ones).

The product of its digits is 69984, while the sum is 36.

The square root of 638633331 is about 25271.1956780838. The cubic root of 638633331 is about 861.1600223801.

The spelling of 638633331 in words is "six hundred thirty-eight million, six hundred thirty-three thousand, three hundred thirty-one".