1221331312 has 20 divisors (see below), whose sum is σ = 2367044680. Its totient is φ = 610481088.

The previous prime is 1221331301. The next prime is 1221331313. The reversal of 1221331312 is 2131331221.

It is a self number, because there is not a number n which added to its sum of digits gives 1221331312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221331313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54514 + ... + 73582.

It is an arithmetic number, because the mean of its divisors is an integer number (118352234).

Almost surely, 2^1221331312 is an apocalyptic number.

It is an amenable number.

1221331312 is a deficient number, since it is larger than the sum of its proper divisors (1145713368).

1221331312 is a wasteful number, since it uses less digits than its factorization.

1221331312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23080 (or 23074 counting only the distinct ones).

The product of its digits is 216, while the sum is 19.

The square root of 1221331312 is about 34947.5508727007. The cubic root of 1221331312 is about 1068.9182627498.

Adding to 1221331312 its reverse (2131331221), we get a palindrome (3352662533).

Subtracting 1221331312 from its reverse (2131331221), we obtain a palindrome (909999909).

The spelling of 1221331312 in words is "one billion, two hundred twenty-one million, three hundred thirty-one thousand, three hundred twelve".