1231312321 has 4 divisors (see below), whose sum is σ = 1231432132. Its totient is φ = 1231192512.

The previous prime is 1231312319. The next prime is 1231312333. The reversal of 1231312321 is 1232131321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 732460096 + 498852225 = 27064^2 + 22335^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231312321 - 2¹ = 1231312319 is a prime.

It is a super-2 number, since 2×1231312321² = 3032260063692814082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231312351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42876 + ... + 65581.

It is an arithmetic number, because the mean of its divisors is an integer number (307858033).

Almost surely, 2^1231312321 is an apocalyptic number.

It is an amenable number.

1231312321 is a deficient number, since it is larger than the sum of its proper divisors (119811).

1231312321 is a wasteful number, since it uses less digits than its factorization.

1231312321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119810.

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

The square root of 1231312321 is about 35090.0601452890. The cubic root of 1231312321 is about 1071.8221843560.

Adding to 1231312321 its reverse (1232131321), we get a palindrome (2463443642).

The spelling of 1231312321 in words is "one billion, two hundred thirty-one million, three hundred twelve thousand, three hundred twenty-one".