23981921 has 2 divisors, whose sum is σ = 23981922. Its totient is φ = 23981920.

The previous prime is 23981899. The next prime is 23981953. The reversal of 23981921 is 12918932.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14440000 + 9541921 = 3800^2 + 3089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23981921 is a prime.

It is not a weakly prime, because it can be changed into another prime (23981981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11990960 + 11990961.

It is an arithmetic number, because the mean of its divisors is an integer number (11990961).

Almost surely, 2^23981921 is an apocalyptic number.

It is an amenable number.

23981921 is a deficient number, since it is larger than the sum of its proper divisors (1).

23981921 is an equidigital number, since it uses as much as digits as its factorization.

23981921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The square root of 23981921 is about 4897.1339577349. The cubic root of 23981921 is about 288.3774668950.

The spelling of 23981921 in words is "twenty-three million, nine hundred eighty-one thousand, nine hundred twenty-one".