138239999 has 2 divisors, whose sum is σ = 138240000. Its totient is φ = 138239998.

The previous prime is 138239963. The next prime is 138240061. The reversal of 138239999 is 999932831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138239999 - 2²⁰ = 137191423 is a prime.

It is a super-2 number, since 2×138239999² = 38220594647040002, which contains 22 as substring.

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 138239999.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138239929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69119999 + 69120000.

It is an arithmetic number, because the mean of its divisors is an integer number (69120000).

Almost surely, 2^138239999 is an apocalyptic number.

138239999 is a deficient number, since it is larger than the sum of its proper divisors (1).

138239999 is an equidigital number, since it uses as much as digits as its factorization.

138239999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 944784, while the sum is 53.

The square root of 138239999 is about 11757.5507228334. The cubic root of 138239999 is about 517.0643243609.

The spelling of 138239999 in words is "one hundred thirty-eight million, two hundred thirty-nine thousand, nine hundred ninety-nine".