1321021321 has 4 divisors (see below), whose sum is σ = 1363634944. Its totient is φ = 1278407700.

The previous prime is 1321021291. The next prime is 1321021337. The reversal of 1321021321 is 1231201231.

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: 1231201231 = 13 ⋅94707787.

It is a cyclic number.

It is not a de Polignac number, because 1321021321 - 2¹³ = 1321013129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1321021295 and 1321021304.

It is not an unprimeable number, because it can be changed into a prime (1321027321) 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, 21306765 + ... + 21306826.

It is an arithmetic number, because the mean of its divisors is an integer number (340908736).

Almost surely, 2^1321021321 is an apocalyptic number.

It is an amenable number.

1321021321 is a deficient number, since it is larger than the sum of its proper divisors (42613623).

1321021321 is an equidigital number, since it uses as much as digits as its factorization.

1321021321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42613622.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1321021321 is about 36345.8569991134. The cubic root of 1321021321 is about 1097.2441541224.

Adding to 1321021321 its reverse (1231201231), we get a palindrome (2552222552).

The spelling of 1321021321 in words is "one billion, three hundred twenty-one million, twenty-one thousand, three hundred twenty-one".