23721661 has 2 divisors, whose sum is σ = 23721662. Its totient is φ = 23721660.

The previous prime is 23721653. The next prime is 23721667. The reversal of 23721661 is 16612732.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23716900 + 4761 = 4870^2 + 69^2 .

It is a cyclic number.

It is not a de Polignac number, because 23721661 - 2³ = 23721653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23721667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11860830 + 11860831.

It is an arithmetic number, because the mean of its divisors is an integer number (11860831).

Almost surely, 2^23721661 is an apocalyptic number.

It is an amenable number.

23721661 is a deficient number, since it is larger than the sum of its proper divisors (1).

23721661 is an equidigital number, since it uses as much as digits as its factorization.

23721661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

The square root of 23721661 is about 4870.4887845061. The cubic root of 23721661 is about 287.3304800270.

The spelling of 23721661 in words is "twenty-three million, seven hundred twenty-one thousand, six hundred sixty-one".