1321322021 has 4 divisors (see below), whose sum is σ = 1363945344. Its totient is φ = 1278698700.

The previous prime is 1321321993. The next prime is 1321322033. The reversal of 1321322021 is 1202231231.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321322021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321322071) 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, 21311615 + ... + 21311676.

It is an arithmetic number, because the mean of its divisors is an integer number (340986336).

Almost surely, 2^1321322021 is an apocalyptic number.

It is an amenable number.

1321322021 is a deficient number, since it is larger than the sum of its proper divisors (42623323).

1321322021 is an equidigital number, since it uses as much as digits as its factorization.

1321322021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42623322.

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

The square root of 1321322021 is about 36349.9934112786. The cubic root of 1321322021 is about 1097.3274019046.

Adding to 1321322021 its reverse (1202231231), we get a palindrome (2523553252).

The spelling of 1321322021 in words is "one billion, three hundred twenty-one million, three hundred twenty-two thousand, twenty-one".