638468977 has 2 divisors, whose sum is σ = 638468978. Its totient is φ = 638468976.

The previous prime is 638468969. The next prime is 638469011. The reversal of 638468977 is 779864836.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 384512881 + 253956096 = 19609^2 + 15936^2 .

It is a cyclic number.

It is not a de Polignac number, because 638468977 - 2³ = 638468969 is a prime.

It is not a weakly prime, because it can be changed into another prime (638468927) 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 as a sum of consecutive naturals, namely, 319234488 + 319234489.

It is an arithmetic number, because the mean of its divisors is an integer number (319234489).

Almost surely, 2^638468977 is an apocalyptic number.

It is an amenable number.

638468977 is a deficient number, since it is larger than the sum of its proper divisors (1).

638468977 is an equidigital number, since it uses as much as digits as its factorization.

638468977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12192768, while the sum is 58.

The square root of 638468977 is about 25267.9436638599. The cubic root of 638468977 is about 861.0861420951.

The spelling of 638468977 in words is "six hundred thirty-eight million, four hundred sixty-eight thousand, nine hundred seventy-seven".