1291779319 has 2 divisors, whose sum is σ = 1291779320. Its totient is φ = 1291779318.

The previous prime is 1291779317. The next prime is 1291779343. The reversal of 1291779319 is 9139771921.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1291779319 - 2¹ = 1291779317 is a prime.

It is a super-2 number, since 2×1291779319² = 3337387617992207522, which contains 22 as substring.

Together with 1291779317, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291779317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645889659 + 645889660.

It is an arithmetic number, because the mean of its divisors is an integer number (645889660).

Almost surely, 2^1291779319 is an apocalyptic number.

1291779319 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291779319 is an equidigital number, since it uses as much as digits as its factorization.

1291779319 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 214326, while the sum is 49.

The square root of 1291779319 is about 35941.3316253029. The cubic root of 1291779319 is about 1089.0875058240.

The spelling of 1291779319 in words is "one billion, two hundred ninety-one million, seven hundred seventy-nine thousand, three hundred nineteen".