1291291291 has 2 divisors, whose sum is σ = 1291291292. Its totient is φ = 1291291290.

The previous prime is 1291291289. The next prime is 1291291303. The reversal of 1291291291 is 1921921921.

It is a weak prime.

It is an emirp because it is prime and its reverse (1921921921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291291291 - 2¹ = 1291291289 is a prime.

Together with 1291291289, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1291291291.

It is not a weakly prime, because it can be changed into another prime (1294291291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645645645 + 645645646.

It is an arithmetic number, because the mean of its divisors is an integer number (645645646).

Almost surely, 2^1291291291 is an apocalyptic number.

1291291291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291291291 is an equidigital number, since it uses as much as digits as its factorization.

1291291291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 37.

The square root of 1291291291 is about 35934.5417530264. The cubic root of 1291291291 is about 1088.9503378788.

The spelling of 1291291291 in words is "one billion, two hundred ninety-one million, two hundred ninety-one thousand, two hundred ninety-one".