1221031312 has 20 divisors (see below), whose sum is σ = 2447326620. Its totient is φ = 589463168.

The previous prime is 1221031297. The next prime is 1221031313. The reversal of 1221031312 is 2131301221.

It can be written as a sum of positive squares in 2 ways, for example, as 330366976 + 890664336 = 18176^2 + 29844^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (1221031313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1315303 + ... + 1316230.

It is an arithmetic number, because the mean of its divisors is an integer number (122366331).

Almost surely, 2^1221031312 is an apocalyptic number.

It is an amenable number.

1221031312 is an abundant number, since it is smaller than the sum of its proper divisors (1226295308).

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

1221031312 is a wasteful number, since it uses less digits than its factorization.

1221031312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631570 (or 2631564 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1221031312 is about 34943.2584628280. The cubic root of 1221031312 is about 1068.8307348378.

Adding to 1221031312 its reverse (2131301221), we get a palindrome (3352332533).

The spelling of 1221031312 in words is "one billion, two hundred twenty-one million, thirty-one thousand, three hundred twelve".