138566331 has 12 divisors (see below), whose sum is σ = 200404152. Its totient is φ = 92260896.

The previous prime is 138566317. The next prime is 138566333. The reversal of 138566331 is 133665831.

It is a happy number.

138566331 is a `hidden beast` number, since 13 + 8 + 5 + 6 + 633 + 1 = 666.

It is not a de Polignac number, because 138566331 - 2⁵ = 138566299 is a prime.

It is a super-2 number, since 2×138566331² = 38401256173603122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138566333) 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 11 ways as a sum of consecutive naturals, for example, 1866 + ... + 16751.

It is an arithmetic number, because the mean of its divisors is an integer number (16700346).

Almost surely, 2^138566331 is an apocalyptic number.

138566331 is a deficient number, since it is larger than the sum of its proper divisors (61837821).

138566331 is a wasteful number, since it uses less digits than its factorization.

138566331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19450 (or 19447 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 138566331 is about 11771.4200927501. The cubic root of 138566331 is about 517.4708686255.

The spelling of 138566331 in words is "one hundred thirty-eight million, five hundred sixty-six thousand, three hundred thirty-one".