638900489 has 2 divisors, whose sum is σ = 638900490. Its totient is φ = 638900488.

The previous prime is 638900467. The next prime is 638900567. The reversal of 638900489 is 984009836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 496933264 + 141967225 = 22292^2 + 11915^2 .

It is a cyclic number.

It is not a de Polignac number, because 638900489 - 2¹² = 638896393 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (638900429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319450244 + 319450245.

It is an arithmetic number, because the mean of its divisors is an integer number (319450245).

Almost surely, 2^638900489 is an apocalyptic number.

It is an amenable number.

638900489 is a deficient number, since it is larger than the sum of its proper divisors (1).

638900489 is an equidigital number, since it uses as much as digits as its factorization.

638900489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 47.

The square root of 638900489 is about 25276.4809457329. The cubic root of 638900489 is about 861.2800879977.

The spelling of 638900489 in words is "six hundred thirty-eight million, nine hundred thousand, four hundred eighty-nine".