638793819 has 12 divisors (see below), whose sum is σ = 976979016. Its totient is φ = 400811712.

The previous prime is 638793811. The next prime is 638793829. The reversal of 638793819 is 918397836.

It is not a de Polignac number, because 638793819 - 2³ = 638793811 is a prime.

It is a super-2 number, since 2×638793819² = 816115086385209522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (638793811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2087409 + ... + 2087714.

It is an arithmetic number, because the mean of its divisors is an integer number (81414918).

Almost surely, 2^638793819 is an apocalyptic number.

638793819 is a deficient number, since it is larger than the sum of its proper divisors (338185197).

638793819 is a wasteful number, since it uses less digits than its factorization.

638793819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4175146 (or 4175143 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The square root of 638793819 is about 25274.3707933551. The cubic root of 638793819 is about 861.2321525930.

The spelling of 638793819 in words is "six hundred thirty-eight million, seven hundred ninety-three thousand, eight hundred nineteen".