221215224 has 32 divisors (see below), whose sum is σ = 558213120. Its totient is φ = 73048416.

The previous prime is 221215223. The next prime is 221215231. The reversal of 221215224 is 422512122.

It is a self number, because there is not a number n which added to its sum of digits gives 221215224.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221215223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40504 + ... + 45639.

It is an arithmetic number, because the mean of its divisors is an integer number (17444160).

Almost surely, 2^221215224 is an apocalyptic number.

221215224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

221215224 is an abundant number, since it is smaller than the sum of its proper divisors (336997896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221215224 is a wasteful number, since it uses less digits than its factorization.

221215224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86259 (or 86255 counting only the distinct ones).

The product of its digits is 640, while the sum is 21.

The square root of 221215224 is about 14873.3057522529. The cubic root of 221215224 is about 604.7905602023.

Adding to 221215224 its reverse (422512122), we get a palindrome (643727346).

The spelling of 221215224 in words is "two hundred twenty-one million, two hundred fifteen thousand, two hundred twenty-four".