1321223021 has 2 divisors, whose sum is σ = 1321223022. Its totient is φ = 1321223020.

The previous prime is 1321223011. The next prime is 1321223023. The reversal of 1321223021 is 1203221231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1225770121 + 95452900 = 35011^2 + 9770^2 .

It is an emirp because it is prime and its reverse (1203221231) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1321223021 - 2⁶ = 1321222957 is a prime.

Together with 1321223023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321223023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660611510 + 660611511.

It is an arithmetic number, because the mean of its divisors is an integer number (660611511).

Almost surely, 2^1321223021 is an apocalyptic number.

It is an amenable number.

1321223021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321223021 is an equidigital number, since it uses as much as digits as its factorization.

1321223021 is an evil number, because the sum of its binary digits is even.

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

The square root of 1321223021 is about 36348.6316248631. The cubic root of 1321223021 is about 1097.2999954828.

Adding to 1321223021 its reverse (1203221231), we get a palindrome (2524444252).

The spelling of 1321223021 in words is "one billion, three hundred twenty-one million, two hundred twenty-three thousand, twenty-one".