1321220231 has 4 divisors (see below), whose sum is σ = 1321311264. Its totient is φ = 1321129200.

The previous prime is 1321220227. The next prime is 1321220249. The reversal of 1321220231 is 1320221231.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1321220231 - 2² = 1321220227 is a prime.

It is a super-2 number, since 2×1321220231² = 3491245797607386722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321220291) 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, 18335 + ... + 54576.

It is an arithmetic number, because the mean of its divisors is an integer number (330327816).

Almost surely, 2^1321220231 is an apocalyptic number.

1321220231 is a deficient number, since it is larger than the sum of its proper divisors (91033).

1321220231 is an equidigital number, since it uses as much as digits as its factorization.

1321220231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91032.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1321220231 is about 36348.5932465068. The cubic root of 1321220231 is about 1097.2992231002.

Adding to 1321220231 its reverse (1320221231), we get a palindrome (2641441462).

The spelling of 1321220231 in words is "one billion, three hundred twenty-one million, two hundred twenty thousand, two hundred thirty-one".