1331221291 has 2 divisors, whose sum is σ = 1331221292. Its totient is φ = 1331221290.

The previous prime is 1331221289. The next prime is 1331221321. The reversal of 1331221291 is 1921221331.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1331221291 - 2¹ = 1331221289 is a prime.

It is a super-2 number, since 2×1331221291² = 3544300251223413362, which contains 22 as substring.

Together with 1331221289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1331221231) 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 as a sum of consecutive naturals, namely, 665610645 + 665610646.

It is an arithmetic number, because the mean of its divisors is an integer number (665610646).

Almost surely, 2^1331221291 is an apocalyptic number.

1331221291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331221291 is an equidigital number, since it uses as much as digits as its factorization.

1331221291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 25.

The square root of 1331221291 is about 36485.9053745416. The cubic root of 1331221291 is about 1100.0609583298.

The spelling of 1331221291 in words is "one billion, three hundred thirty-one million, two hundred twenty-one thousand, two hundred ninety-one".