138194989 has 4 divisors (see below), whose sum is σ = 146324124. Its totient is φ = 130065856.

The previous prime is 138194983. The next prime is 138195007. The reversal of 138194989 is 989491831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62678889 + 75516100 = 7917^2 + 8690^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138194989 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 (138194983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4064542 + ... + 4064575.

It is an arithmetic number, because the mean of its divisors is an integer number (36581031).

Almost surely, 2^138194989 is an apocalyptic number.

It is an amenable number.

138194989 is a deficient number, since it is larger than the sum of its proper divisors (8129135).

138194989 is an equidigital number, since it uses as much as digits as its factorization.

138194989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8129134.

The product of its digits is 559872, while the sum is 52.

The square root of 138194989 is about 11755.6364778773. The cubic root of 138194989 is about 517.0082007312.

The spelling of 138194989 in words is "one hundred thirty-eight million, one hundred ninety-four thousand, nine hundred eighty-nine".