221215312 has 10 divisors (see below), whose sum is σ = 428604698. Its totient is φ = 110607648.

The previous prime is 221215301. The next prime is 221215321. The reversal of 221215312 is 213512122.

It can be written as a sum of positive squares in only one way, i.e., 157151296 + 64064016 = 12536^2 + 8004^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 221215312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6912963 + ... + 6912994.

Almost surely, 2^221215312 is an apocalyptic number.

It is an amenable number.

221215312 is a deficient number, since it is larger than the sum of its proper divisors (207389386).

221215312 is a wasteful number, since it uses less digits than its factorization.

221215312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13825965 (or 13825959 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 221215312 is about 14873.3087105728. The cubic root of 221215312 is about 604.7906403981.

Adding to 221215312 its reverse (213512122), we get a palindrome (434727434).

The spelling of 221215312 in words is "two hundred twenty-one million, two hundred fifteen thousand, three hundred twelve".