138815523 has 48 divisors (see below), whose sum is σ = 264715776. Its totient is φ = 67864320.

The previous prime is 138815519. The next prime is 138815531. The reversal of 138815523 is 325518831.

It is a Cunningham number, because it is equal to 11782²-1.

It is not a de Polignac number, because 138815523 - 2² = 138815519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138815513) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5890 + ... + 17672.

It is an arithmetic number, because the mean of its divisors is an integer number (5514912).

Almost surely, 2^138815523 is an apocalyptic number.

138815523 is a deficient number, since it is larger than the sum of its proper divisors (125900253).

138815523 is a wasteful number, since it uses less digits than its factorization.

138815523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11824 (or 11821 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 138815523 is about 11781.9999575624. Note that the first 4 decimals coincide. The cubic root of 138815523 is about 517.7808823152.

The spelling of 138815523 in words is "one hundred thirty-eight million, eight hundred fifteen thousand, five hundred twenty-three".