638532859 has 2 divisors, whose sum is σ = 638532860. Its totient is φ = 638532858.

The previous prime is 638532857. The next prime is 638532871. The reversal of 638532859 is 958235836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638532859 - 2¹ = 638532857 is a prime.

Together with 638532857, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (638532857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319266429 + 319266430.

It is an arithmetic number, because the mean of its divisors is an integer number (319266430).

Almost surely, 2^638532859 is an apocalyptic number.

638532859 is a deficient number, since it is larger than the sum of its proper divisors (1).

638532859 is an equidigital number, since it uses as much as digits as its factorization.

638532859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1555200, while the sum is 49.

The square root of 638532859 is about 25269.2077240265. The cubic root of 638532859 is about 861.1148597893.

The spelling of 638532859 in words is "six hundred thirty-eight million, five hundred thirty-two thousand, eight hundred fifty-nine".