138243902 has 4 divisors (see below), whose sum is σ = 207365856. Its totient is φ = 69121950.

The previous prime is 138243901. The next prime is 138243913. The reversal of 138243902 is 209342831.

It is a happy number.

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

It is a super-2 number, since 2×138243902² = 38222752880371208, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138243901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34560974 + ... + 34560977.

It is an arithmetic number, because the mean of its divisors is an integer number (51841464).

Almost surely, 2^138243902 is an apocalyptic number.

138243902 is a deficient number, since it is larger than the sum of its proper divisors (69121954).

138243902 is an equidigital number, since it uses as much as digits as its factorization.

138243902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69121953.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 138243902 is about 11757.7167001081. The cubic root of 138243902 is about 517.0691904948.

The spelling of 138243902 in words is "one hundred thirty-eight million, two hundred forty-three thousand, nine hundred two".