1321213321 has 4 divisors (see below), whose sum is σ = 1327033872. Its totient is φ = 1315392772.

The previous prime is 1321213253. The next prime is 1321213331. The reversal of 1321213321 is 1233121231.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1233121231 = 17 ⋅72536543.

It is a cyclic number.

It is not a de Polignac number, because 1321213321 - 2²⁹ = 784342409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321213331) 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, 2909935 + ... + 2910388.

It is an arithmetic number, because the mean of its divisors is an integer number (331758468).

Almost surely, 2^1321213321 is an apocalyptic number.

It is an amenable number.

1321213321 is a deficient number, since it is larger than the sum of its proper divisors (5820551).

1321213321 is an equidigital number, since it uses as much as digits as its factorization.

1321213321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5820550.

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

The square root of 1321213321 is about 36348.4981945609. The cubic root of 1321213321 is about 1097.2973101335.

Adding to 1321213321 its reverse (1233121231), we get a palindrome (2554334552).

The spelling of 1321213321 in words is "one billion, three hundred twenty-one million, two hundred thirteen thousand, three hundred twenty-one".