638512873 has 2 divisors, whose sum is σ = 638512874. Its totient is φ = 638512872.

The previous prime is 638512799. The next prime is 638512883. The reversal of 638512873 is 378215836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 574704729 + 63808144 = 23973^2 + 7988^2 .

It is a cyclic number.

It is not a de Polignac number, because 638512873 - 2²¹ = 636415721 is a prime.

It is not a weakly prime, because it can be changed into another prime (638512883) by changing a digit.

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 as a sum of consecutive naturals, namely, 319256436 + 319256437.

It is an arithmetic number, because the mean of its divisors is an integer number (319256437).

Almost surely, 2^638512873 is an apocalyptic number.

It is an amenable number.

638512873 is a deficient number, since it is larger than the sum of its proper divisors (1).

638512873 is an equidigital number, since it uses as much as digits as its factorization.

638512873 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 43.

The square root of 638512873 is about 25268.8122593841. The cubic root of 638512873 is about 861.1058754325.

The spelling of 638512873 in words is "six hundred thirty-eight million, five hundred twelve thousand, eight hundred seventy-three".