1231031221 has 4 divisors (see below), whose sum is σ = 1406892832. Its totient is φ = 1055169612.

The previous prime is 1231031213. The next prime is 1231031233. The reversal of 1231031221 is 1221301321.

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.

It is not a de Polignac number, because 1231031221 - 2³ = 1231031213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231031195 and 1231031204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231031621) 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, 87930795 + ... + 87930808.

It is an arithmetic number, because the mean of its divisors is an integer number (351723208).

Almost surely, 2^1231031221 is an apocalyptic number.

It is an amenable number.

1231031221 is a deficient number, since it is larger than the sum of its proper divisors (175861611).

1231031221 is an equidigital number, since it uses as much as digits as its factorization.

1231031221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175861610.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1231031221 is about 35086.0545088786. The cubic root of 1231031221 is about 1071.7406149764.

Adding to 1231031221 its reverse (1221301321), we get a palindrome (2452332542).

The spelling of 1231031221 in words is "one billion, two hundred thirty-one million, thirty-one thousand, two hundred twenty-one".