1312231321 has 4 divisors (see below), whose sum is σ = 1312316032. Its totient is φ = 1312146612.

The previous prime is 1312231313. The next prime is 1312231339. The reversal of 1312231321 is 1231322131.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1231322131 = 13 ⋅94717087.

It is a cyclic number.

It is not a de Polignac number, because 1312231321 - 2³ = 1312231313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1312234321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11745 + ... + 52558.

It is an arithmetic number, because the mean of its divisors is an integer number (328079008).

Almost surely, 2^1312231321 is an apocalyptic number.

It is an amenable number.

1312231321 is a deficient number, since it is larger than the sum of its proper divisors (84711).

1312231321 is an equidigital number, since it uses as much as digits as its factorization.

1312231321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84710.

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

The square root of 1312231321 is about 36224.7335531954. The cubic root of 1312231321 is about 1094.8050697260.

Adding to 1312231321 its reverse (1231322131), we get a palindrome (2543553452).

The spelling of 1312231321 in words is "one billion, three hundred twelve million, two hundred thirty-one thousand, three hundred twenty-one".