23155221 has 4 divisors (see below), whose sum is σ = 30873632. Its totient is φ = 15436812.

The previous prime is 23155217. The next prime is 23155247. The reversal of 23155221 is 12255132.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 23155221 - 2² = 23155217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23155271) 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, 3859201 + ... + 3859206.

It is an arithmetic number, because the mean of its divisors is an integer number (7718408).

Almost surely, 2^23155221 is an apocalyptic number.

It is an amenable number.

23155221 is a deficient number, since it is larger than the sum of its proper divisors (7718411).

23155221 is an equidigital number, since it uses as much as digits as its factorization.

23155221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7718410.

The product of its digits is 600, while the sum is 21.

The square root of 23155221 is about 4811.9872194344. The cubic root of 23155221 is about 285.0250147327.

The spelling of 23155221 in words is "twenty-three million, one hundred fifty-five thousand, two hundred twenty-one".