1231321013 has 16 divisors (see below), whose sum is σ = 1338587376. Its totient is φ = 1125895680.

The previous prime is 1231321001. The next prime is 1231321043. The reversal of 1231321013 is 3101231321.

It can be written as a sum of positive squares in 8 ways, for example, as 262991089 + 968329924 = 16217^2 + 31118^2 .

It is not a de Polignac number, because 1231321013 - 2⁶ = 1231320949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231320982 and 1231321000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231321043) 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 15 ways as a sum of consecutive naturals, for example, 858545 + ... + 859977.

It is an arithmetic number, because the mean of its divisors is an integer number (83661711).

Almost surely, 2^1231321013 is an apocalyptic number.

1231321013 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1231321013 is a deficient number, since it is larger than the sum of its proper divisors (107266363).

1231321013 is a wasteful number, since it uses less digits than its factorization.

1231321013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2024.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1231321013 is about 35090.1839978077. The cubic root of 1231321013 is about 1071.8247063959.

Adding to 1231321013 its reverse (3101231321), we get a palindrome (4332552334).

The spelling of 1231321013 in words is "one billion, two hundred thirty-one million, three hundred twenty-one thousand, thirteen".