23209661 has 2 divisors, whose sum is σ = 23209662. Its totient is φ = 23209660.

The previous prime is 23209651. The next prime is 23209673. The reversal of 23209661 is 16690232.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18757561 + 4452100 = 4331^2 + 2110^2 .

It is a cyclic number.

It is not a de Polignac number, because 23209661 - 2¹⁸ = 22947517 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23209651) 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 as a sum of consecutive naturals, namely, 11604830 + 11604831.

It is an arithmetic number, because the mean of its divisors is an integer number (11604831).

Almost surely, 2^23209661 is an apocalyptic number.

It is an amenable number.

23209661 is a deficient number, since it is larger than the sum of its proper divisors (1).

23209661 is an equidigital number, since it uses as much as digits as its factorization.

23209661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 23209661 is about 4817.6406051095. The cubic root of 23209661 is about 285.2482130231.

Adding to 23209661 its reverse (16690232), we get a palindrome (39899893).

The spelling of 23209661 in words is "twenty-three million, two hundred nine thousand, six hundred sixty-one".