23201621 has 2 divisors, whose sum is σ = 23201622. Its totient is φ = 23201620.

The previous prime is 23201599. The next prime is 23201623. The reversal of 23201621 is 12610232.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19704721 + 3496900 = 4439^2 + 1870^2 .

It is a cyclic number.

It is not a de Polignac number, because 23201621 - 2⁶ = 23201557 is a prime.

It is a Sophie Germain prime.

Together with 23201623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 23201621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23201623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11600810 + 11600811.

It is an arithmetic number, because the mean of its divisors is an integer number (11600811).

Almost surely, 2^23201621 is an apocalyptic number.

It is an amenable number.

23201621 is a deficient number, since it is larger than the sum of its proper divisors (1).

23201621 is an equidigital number, since it uses as much as digits as its factorization.

23201621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 23201621 is about 4816.8060994813. The cubic root of 23201621 is about 285.2152718483.

Adding to 23201621 its reverse (12610232), we get a palindrome (35811853).

The spelling of 23201621 in words is "twenty-three million, two hundred one thousand, six hundred twenty-one".