1221215312 has 10 divisors (see below), whose sum is σ = 2366104698. Its totient is φ = 610607648.

The previous prime is 1221215311. The next prime is 1221215339. The reversal of 1221215312 is 2135121221.

It can be written as a sum of positive squares in only one way, i.e., 1086097936 + 135117376 = 32956^2 + 11624^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221215311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38162963 + ... + 38162994.

Almost surely, 2^1221215312 is an apocalyptic number.

It is an amenable number.

1221215312 is a deficient number, since it is larger than the sum of its proper divisors (1144889386).

1221215312 is an equidigital number, since it uses as much as digits as its factorization.

1221215312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76325965 (or 76325959 counting only the distinct ones).

The product of its digits is 240, while the sum is 20.

The square root of 1221215312 is about 34945.8912034019. The cubic root of 1221215312 is about 1068.8844203236.

Adding to 1221215312 its reverse (2135121221), we get a palindrome (3356336533).

The spelling of 1221215312 in words is "one billion, two hundred twenty-one million, two hundred fifteen thousand, three hundred twelve".