638563005 has 18 divisors (see below), whose sum is σ = 1107136446. Its totient is φ = 340476528.

The previous prime is 638562973. The next prime is 638563019. The reversal of 638563005 is 500365836.

It can be written as a sum of positive squares in only one way, i.e., 510850404 + 127712601 = 22602^2 + 11301^2 .

It is not a de Polignac number, because 638563005 - 2⁵ = 638562973 is a prime.

It is a super-2 number, since 2×638563005² = 815525422709260050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 167632 + ... + 171398.

Almost surely, 2^638563005 is an apocalyptic number.

It is an amenable number.

638563005 is a deficient number, since it is larger than the sum of its proper divisors (468573441).

638563005 is an frugal number, since it uses more digits than its factorization.

638563005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7545 (or 3775 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 638563005 is about 25269.8042137251. The cubic root of 638563005 is about 861.1284110418.

The spelling of 638563005 in words is "six hundred thirty-eight million, five hundred sixty-three thousand, five".