1221320323 has 4 divisors (see below), whose sum is σ = 1285600360. Its totient is φ = 1157040288.

The previous prime is 1221320293. The next prime is 1221320371. The reversal of 1221320323 is 3230231221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221320323 - 2⁵ = 1221320291 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 64280017 = 1221320323 / (1 + 2 + 2 + 1 + 3 + 2 + 0 + 3 + 2 + 3).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221320323.

It is not an unprimeable number, because it can be changed into a prime (1221120323) 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, 32139990 + ... + 32140027.

It is an arithmetic number, because the mean of its divisors is an integer number (321400090).

Almost surely, 2^1221320323 is an apocalyptic number.

1221320323 is a deficient number, since it is larger than the sum of its proper divisors (64280037).

1221320323 is an equidigital number, since it uses as much as digits as its factorization.

1221320323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64280036.

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 1221320323 is about 34947.3936510293. The cubic root of 1221320323 is about 1068.9150568553.

Adding to 1221320323 its reverse (3230231221), we get a palindrome (4451551544).

The spelling of 1221320323 in words is "one billion, two hundred twenty-one million, three hundred twenty thousand, three hundred twenty-three".