1221312231 has 24 divisors (see below), whose sum is σ = 1814276880. Its totient is φ = 791346816.

The previous prime is 1221312217. The next prime is 1221312269. The reversal of 1221312231 is 1322131221.

1221312231 is a `hidden beast` number, since 122 + 1 + 312 + 231 = 666.

It is not a de Polignac number, because 1221312231 - 2⁵ = 1221312199 is a prime.

It is a super-2 number, since 2×1221312231² = 2983207131180394722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221312031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39075 + ... + 63003.

It is an arithmetic number, because the mean of its divisors is an integer number (75594870).

Almost surely, 2^1221312231 is an apocalyptic number.

1221312231 is a deficient number, since it is larger than the sum of its proper divisors (592964649).

1221312231 is a wasteful number, since it uses less digits than its factorization.

1221312231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24095 (or 24092 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 1221312231 is about 34947.2778768247. The cubic root of 1221312231 is about 1068.9126961097.

Adding to 1221312231 its reverse (1322131221), we get a palindrome (2543443452).

The spelling of 1221312231 in words is "one billion, two hundred twenty-one million, three hundred twelve thousand, two hundred thirty-one".