638888113 has 2 divisors, whose sum is σ = 638888114. Its totient is φ = 638888112.

The previous prime is 638888111. The next prime is 638888141. The reversal of 638888113 is 311888836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 632623104 + 6265009 = 25152^2 + 2503^2 .

It is a cyclic number.

It is not a de Polignac number, because 638888113 - 2¹ = 638888111 is a prime.

Together with 638888111, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (638888111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319444056 + 319444057.

It is an arithmetic number, because the mean of its divisors is an integer number (319444057).

Almost surely, 2^638888113 is an apocalyptic number.

It is an amenable number.

638888113 is a deficient number, since it is larger than the sum of its proper divisors (1).

638888113 is an equidigital number, since it uses as much as digits as its factorization.

638888113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 221184, while the sum is 46.

The square root of 638888113 is about 25276.2361319877. The cubic root of 638888113 is about 861.2745267397.

The spelling of 638888113 in words is "six hundred thirty-eight million, eight hundred eighty-eight thousand, one hundred thirteen".