1221302321 has 4 divisors (see below), whose sum is σ = 1293143652. Its totient is φ = 1149460992.

The previous prime is 1221302281. The next prime is 1221302333. The reversal of 1221302321 is 1232031221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1232031221 = 229 ⋅5380049.

It can be written as a sum of positive squares in 2 ways, for example, as 873852721 + 347449600 = 29561^2 + 18640^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221302321 - 2²² = 1217108017 is a prime.

It is a super-3 number, since 3×1221302321³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 71841313 = 1221302321 / (1 + 2 + 2 + 1 + 3 + 0 + 2 + 3 + 2 + 1).

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 1221302321.

It is not an unprimeable number, because it can be changed into a prime (1221302371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35920640 + ... + 35920673.

It is an arithmetic number, because the mean of its divisors is an integer number (323285913).

Almost surely, 2^1221302321 is an apocalyptic number.

It is an amenable number.

1221302321 is a deficient number, since it is larger than the sum of its proper divisors (71841331).

1221302321 is an equidigital number, since it uses as much as digits as its factorization.

1221302321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71841330.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1221302321 is about 34947.1360915312. The cubic root of 1221302321 is about 1068.9098049698.

Adding to 1221302321 its reverse (1232031221), we get a palindrome (2453333542).

The spelling of 1221302321 in words is "one billion, two hundred twenty-one million, three hundred two thousand, three hundred twenty-one".