138232391 has 16 divisors (see below), whose sum is σ = 159200640. Its totient is φ = 118703520.

The previous prime is 138232373. The next prime is 138232399. The reversal of 138232391 is 193232831.

It is a cyclic number.

It is not a de Polignac number, because 138232391 - 2⁶ = 138232327 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 (138232399) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91841 + ... + 93333.

It is an arithmetic number, because the mean of its divisors is an integer number (9950040).

Almost surely, 2^138232391 is an apocalyptic number.

138232391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

138232391 is a deficient number, since it is larger than the sum of its proper divisors (20968249).

138232391 is a wasteful number, since it uses less digits than its factorization.

138232391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1966.

The product of its digits is 7776, while the sum is 32.

The square root of 138232391 is about 11757.2271816105. The cubic root of 138232391 is about 517.0548386896.

The spelling of 138232391 in words is "one hundred thirty-eight million, two hundred thirty-two thousand, three hundred ninety-one".