1331312321 has 4 divisors (see below), whose sum is σ = 1338750000. Its totient is φ = 1323874644.

The previous prime is 1331312303. The next prime is 1331312327. The reversal of 1331312321 is 1232131331.

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: 1232131331 = 43 ⋅28654217.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331312321 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1331312293 and 1331312302.

It is not an unprimeable number, because it can be changed into a prime (1331312327) 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, 3718571 + ... + 3718928.

It is an arithmetic number, because the mean of its divisors is an integer number (334687500).

Almost surely, 2^1331312321 is an apocalyptic number.

It is an amenable number.

1331312321 is a deficient number, since it is larger than the sum of its proper divisors (7437679).

1331312321 is an equidigital number, since it uses as much as digits as its factorization.

1331312321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7437678.

The product of its digits is 324, while the sum is 20.

The square root of 1331312321 is about 36487.1528212328. The cubic root of 1331312321 is about 1100.0860321141.

Adding to 1331312321 its reverse (1232131331), we get a palindrome (2563443652).

The spelling of 1331312321 in words is "one billion, three hundred thirty-one million, three hundred twelve thousand, three hundred twenty-one".