23501221 has 4 divisors (see below), whose sum is σ = 23631244. Its totient is φ = 23371200.

The previous prime is 23501171. The next prime is 23501243. The reversal of 23501221 is 12210532.

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 6320196 + 17181025 = 2514^2 + 4145^2 .

It is a cyclic number.

It is not a de Polignac number, because 23501221 - 2⁹ = 23500709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 23501195 and 23501204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23501921) 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 in 3 ways as a sum of consecutive naturals, for example, 64740 + ... + 65101.

It is an arithmetic number, because the mean of its divisors is an integer number (5907811).

Almost surely, 2^23501221 is an apocalyptic number.

It is an amenable number.

23501221 is a deficient number, since it is larger than the sum of its proper divisors (130023).

23501221 is a wasteful number, since it uses less digits than its factorization.

23501221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130022.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 23501221 is about 4847.8057923147. The cubic root of 23501221 is about 286.4376764841.

Adding to 23501221 its reverse (12210532), we get a palindrome (35711753).

The spelling of 23501221 in words is "twenty-three million, five hundred one thousand, two hundred twenty-one".