23539721 has 2 divisors, whose sum is σ = 23539722. Its totient is φ = 23539720.

The previous prime is 23539697. The next prime is 23539729. The reversal of 23539721 is 12793532.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22458121 + 1081600 = 4739^2 + 1040^2 .

It is a cyclic number.

It is not a de Polignac number, because 23539721 - 2¹⁴ = 23523337 is a prime.

It is not a weakly prime, because it can be changed into another prime (23539729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11769860 + 11769861.

It is an arithmetic number, because the mean of its divisors is an integer number (11769861).

Almost surely, 2^23539721 is an apocalyptic number.

It is an amenable number.

23539721 is a deficient number, since it is larger than the sum of its proper divisors (1).

23539721 is an equidigital number, since it uses as much as digits as its factorization.

23539721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11340, while the sum is 32.

The square root of 23539721 is about 4851.7750360049. The cubic root of 23539721 is about 286.5940064329.

The spelling of 23539721 in words is "twenty-three million, five hundred thirty-nine thousand, seven hundred twenty-one".