23991381 has 12 divisors (see below), whose sum is σ = 35849580. Its totient is φ = 15442560.

The previous prime is 23991379. The next prime is 23991389. The reversal of 23991381 is 18319932.

It can be written as a sum of positive squares in 2 ways, for example, as 8071281 + 15920100 = 2841^2 + 3990^2 .

It is not a de Polignac number, because 23991381 - 2¹ = 23991379 is a prime.

It is a super-2 number, since 2×23991381² = 1151172724574322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23991389) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45700 + ... + 46221.

It is an arithmetic number, because the mean of its divisors is an integer number (2987465).

Almost surely, 2^23991381 is an apocalyptic number.

It is an amenable number.

23991381 is a deficient number, since it is larger than the sum of its proper divisors (11858199).

23991381 is a wasteful number, since it uses less digits than its factorization.

23991381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91956 (or 91953 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 23991381 is about 4898.0997335702. The cubic root of 23991381 is about 288.4153800687.

The spelling of 23991381 in words is "twenty-three million, nine hundred ninety-one thousand, three hundred eighty-one".