638608877 has 2 divisors, whose sum is σ = 638608878. Its totient is φ = 638608876.

The previous prime is 638608871. The next prime is 638608967. The reversal of 638608877 is 778806836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 327827236 + 310781641 = 18106^2 + 17629^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638608877 is a prime.

It is a super-2 number, since 2×638608877² = 815642595566402258, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638608871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319304438 + 319304439.

It is an arithmetic number, because the mean of its divisors is an integer number (319304439).

Almost surely, 2^638608877 is an apocalyptic number.

It is an amenable number.

638608877 is a deficient number, since it is larger than the sum of its proper divisors (1).

638608877 is an equidigital number, since it uses as much as digits as its factorization.

638608877 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2709504, while the sum is 53.

The square root of 638608877 is about 25270.7118419723. The cubic root of 638608877 is about 861.1490306394.

The spelling of 638608877 in words is "six hundred thirty-eight million, six hundred eight thousand, eight hundred seventy-seven".