23521621 has 2 divisors, whose sum is σ = 23521622. Its totient is φ = 23521620.

The previous prime is 23521609. The next prime is 23521643. The reversal of 23521621 is 12612532.

It is an a-pointer prime, because the next prime (23521643) can be obtained adding 23521621 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23328900 + 192721 = 4830^2 + 439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23521621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 23521592 and 23521601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23521651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11760810 + 11760811.

It is an arithmetic number, because the mean of its divisors is an integer number (11760811).

Almost surely, 2^23521621 is an apocalyptic number.

It is an amenable number.

23521621 is a deficient number, since it is larger than the sum of its proper divisors (1).

23521621 is an equidigital number, since it uses as much as digits as its factorization.

23521621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 22.

The square root of 23521621 is about 4849.9093805967. The cubic root of 23521621 is about 286.5205323020.

It can be divided in two parts, 23521 and 621, that added together give a palindrome (24142).

The spelling of 23521621 in words is "twenty-three million, five hundred twenty-one thousand, six hundred twenty-one".