138888913 has 2 divisors, whose sum is σ = 138888914. Its totient is φ = 138888912.

The previous prime is 138888907. The next prime is 138888931. The reversal of 138888913 is 319888831.

Together with next prime (138888931) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93837969 + 45050944 = 9687^2 + 6712^2 .

It is a cyclic number.

It is not a de Polignac number, because 138888913 - 2¹⁷ = 138757841 is a prime.

It is not a weakly prime, because it can be changed into another prime (138888943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69444456 + 69444457.

It is an arithmetic number, because the mean of its divisors is an integer number (69444457).

Almost surely, 2^138888913 is an apocalyptic number.

It is an amenable number.

138888913 is a deficient number, since it is larger than the sum of its proper divisors (1).

138888913 is an equidigital number, since it uses as much as digits as its factorization.

138888913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 49.

The square root of 138888913 is about 11785.1140427236. The cubic root of 138888913 is about 517.8721142932.

It can be divided in two parts, 13888 and 8913, that added together give a square (22801 = 151²).

The spelling of 138888913 in words is "one hundred thirty-eight million, eight hundred eighty-eight thousand, nine hundred thirteen".