638725859 has 2 divisors, whose sum is σ = 638725860. Its totient is φ = 638725858.

The previous prime is 638725849. The next prime is 638725897. The reversal of 638725859 is 958527836.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638725859 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638725859.

It is not a weakly prime, because it can be changed into another prime (638725849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319362929 + 319362930.

It is an arithmetic number, because the mean of its divisors is an integer number (319362930).

Almost surely, 2^638725859 is an apocalyptic number.

638725859 is a deficient number, since it is larger than the sum of its proper divisors (1).

638725859 is an equidigital number, since it uses as much as digits as its factorization.

638725859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3628800, while the sum is 53.

The square root of 638725859 is about 25273.0263126520. The cubic root of 638725859 is about 861.2016099197.

The spelling of 638725859 in words is "six hundred thirty-eight million, seven hundred twenty-five thousand, eight hundred fifty-nine".