1231323221 has 4 divisors (see below), whose sum is σ = 1231400352. Its totient is φ = 1231246092.

The previous prime is 1231323199. The next prime is 1231323229. The reversal of 1231323221 is 1223231321.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231323221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1231323193 and 1231323202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231323229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4715 + ... + 49848.

It is an arithmetic number, because the mean of its divisors is an integer number (307850088).

Almost surely, 2^1231323221 is an apocalyptic number.

It is an amenable number.

1231323221 is a deficient number, since it is larger than the sum of its proper divisors (77131).

1231323221 is an equidigital number, since it uses as much as digits as its factorization.

1231323221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77130.

The product of its digits is 432, while the sum is 20.

The square root of 1231323221 is about 35090.2154595836. The cubic root of 1231323221 is about 1071.8253470595.

Adding to 1231323221 its reverse (1223231321), we get a palindrome (2454554542).

The spelling of 1231323221 in words is "one billion, two hundred thirty-one million, three hundred twenty-three thousand, two hundred twenty-one".