15223221 has 48 divisors (see below), whose sum is σ = 25276160. Its totient is φ = 9097920.

The previous prime is 15223213. The next prime is 15223283. The reversal of 15223221 is 12232251.

15223221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 15223221 - 2³ = 15223213 is a prime.

It is a super-2 number, since 2×15223221² = 463492915229682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 15223194 and 15223203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15221221) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 192660 + ... + 192738.

Almost surely, 2^15223221 is an apocalyptic number.

It is an amenable number.

15223221 is a deficient number, since it is larger than the sum of its proper divisors (10052939).

15223221 is an equidigital number, since it uses as much as digits as its factorization.

15223221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168 (or 156 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 15223221 is about 3901.6946318235. The cubic root of 15223221 is about 247.8385449717.

Adding to 15223221 its reverse (12232251), we get a palindrome (27455472).

The spelling of 15223221 in words is "fifteen million, two hundred twenty-three thousand, two hundred twenty-one".