23561221 has 4 divisors (see below), whose sum is σ = 23719500. Its totient is φ = 23402944.

The previous prime is 23561207. The next prime is 23561231. The reversal of 23561221 is 12216532.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4950625 + 18610596 = 2225^2 + 4314^2 .

It is a cyclic number.

It is not a de Polignac number, because 23561221 - 2⁷ = 23561093 is a prime.

It is a super-2 number, since 2×23561221² = 1110262270021682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 23561192 and 23561201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23561231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78916 + ... + 79213.

It is an arithmetic number, because the mean of its divisors is an integer number (5929875).

Almost surely, 2^23561221 is an apocalyptic number.

It is an amenable number.

23561221 is a deficient number, since it is larger than the sum of its proper divisors (158279).

23561221 is a wasteful number, since it uses less digits than its factorization.

23561221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158278.

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

The square root of 23561221 is about 4853.9902142464. The cubic root of 23561221 is about 286.6812334104.

Adding to 23561221 its reverse (12216532), we get a palindrome (35777753).

The spelling of 23561221 in words is "twenty-three million, five hundred sixty-one thousand, two hundred twenty-one".