1221323313 has 32 divisors (see below), whose sum is σ = 1940520960. Its totient is φ = 668485440.

The previous prime is 1221323291. The next prime is 1221323329. The reversal of 1221323313 is 3133231221.

It is not a de Polignac number, because 1221323313 - 2¹⁸ = 1221061169 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 1221323313.

It is not an unprimeable number, because it can be changed into a prime (1221323813) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 69448 + ... + 85238.

It is an arithmetic number, because the mean of its divisors is an integer number (60641280).

Almost surely, 2^1221323313 is an apocalyptic number.

It is an amenable number.

1221323313 is a deficient number, since it is larger than the sum of its proper divisors (719197647).

1221323313 is a wasteful number, since it uses less digits than its factorization.

1221323313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15957.

The product of its digits is 648, while the sum is 21.

The square root of 1221323313 is about 34947.4364295866. The cubic root of 1221323313 is about 1068.9159291499.

Adding to 1221323313 its reverse (3133231221), we get a palindrome (4354554534).

The spelling of 1221323313 in words is "one billion, two hundred twenty-one million, three hundred twenty-three thousand, three hundred thirteen".