23121661 has 2 divisors, whose sum is σ = 23121662. Its totient is φ = 23121660.

The previous prime is 23121643. The next prime is 23121667. The reversal of 23121661 is 16612132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23097636 + 24025 = 4806^2 + 155^2 .

It is a cyclic number.

It is not a de Polignac number, because 23121661 - 2¹⁹ = 22597373 is a prime.

It is a super-2 number, since 2×23121661² = 1069222414797842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23121667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11560830 + 11560831.

It is an arithmetic number, because the mean of its divisors is an integer number (11560831).

Almost surely, 2^23121661 is an apocalyptic number.

It is an amenable number.

23121661 is a deficient number, since it is larger than the sum of its proper divisors (1).

23121661 is an equidigital number, since it uses as much as digits as its factorization.

23121661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 22.

The square root of 23121661 is about 4808.4988301964. The cubic root of 23121661 is about 284.8872478990.

Adding to 23121661 its reverse (16612132), we get a palindrome (39733793).

The spelling of 23121661 in words is "twenty-three million, one hundred twenty-one thousand, six hundred sixty-one".