138571999 has 4 divisors (see below), whose sum is σ = 138746664. Its totient is φ = 138397336.

The previous prime is 138571963. The next prime is 138572003. The reversal of 138571999 is 999175831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 999175831 = 29 ⋅34454339.

It is a cyclic number.

It is not a de Polignac number, because 138571999 - 2⁷ = 138571871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138571399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86137 + ... + 87730.

It is an arithmetic number, because the mean of its divisors is an integer number (34686666).

Almost surely, 2^138571999 is an apocalyptic number.

138571999 is a deficient number, since it is larger than the sum of its proper divisors (174665).

138571999 is an equidigital number, since it uses as much as digits as its factorization.

138571999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174664.

The product of its digits is 612360, while the sum is 52.

The square root of 138571999 is about 11771.6608428887. The cubic root of 138571999 is about 517.4779241752.

The spelling of 138571999 in words is "one hundred thirty-eight million, five hundred seventy-one thousand, nine hundred ninety-nine".