638861542589 has 2 divisors, whose sum is σ = 638861542590. Its totient is φ = 638861542588.

The previous prime is 638861542559. The next prime is 638861542609. The reversal of 638861542589 is 985245168836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 524994439225 + 113867103364 = 724565^2 + 337442^2 .

It is a cyclic number.

It is not a de Polignac number, because 638861542589 - 2³⁶ = 570142065853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638861542559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319430771294 + 319430771295.

It is an arithmetic number, because the mean of its divisors is an integer number (319430771295).

Almost surely, 2^638861542589 is an apocalyptic number.

It is an amenable number.

638861542589 is a deficient number, since it is larger than the sum of its proper divisors (1).

638861542589 is an equidigital number, since it uses as much as digits as its factorization.

638861542589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 99532800, while the sum is 65.

The spelling of 638861542589 in words is "six hundred thirty-eight billion, eight hundred sixty-one million, five hundred forty-two thousand, five hundred eighty-nine".