1291331969 has 2 divisors, whose sum is σ = 1291331970. Its totient is φ = 1291331968.

The previous prime is 1291331957. The next prime is 1291331971. The reversal of 1291331969 is 9691331921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1291324225 + 7744 = 35935^2 + 88^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291331969 - 2⁴ = 1291331953 is a prime.

It is a super-2 number, since 2×1291331969² = 3335076508322833922, which contains 22 as substring.

Together with 1291331971, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1291331989) 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 as a sum of consecutive naturals, namely, 645665984 + 645665985.

It is an arithmetic number, because the mean of its divisors is an integer number (645665985).

Almost surely, 2^1291331969 is an apocalyptic number.

It is an amenable number.

1291331969 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291331969 is an equidigital number, since it uses as much as digits as its factorization.

1291331969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 78732, while the sum is 44.

The square root of 1291331969 is about 35935.1077499428. The cubic root of 1291331969 is about 1088.9617723906.

The spelling of 1291331969 in words is "one billion, two hundred ninety-one million, three hundred thirty-one thousand, nine hundred sixty-nine".