1291817 has 2 divisors, whose sum is σ = 1291818. Its totient is φ = 1291816.

The previous prime is 1291799. The next prime is 1291819. The reversal of 1291817 is 7181921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1201216 + 90601 = 1096^2 + 301^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1291817 is a prime.

It is a super-2 number, since 2×1291817² = 3337582322978, which contains 22 as substring.

Together with 1291819, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1291817.

It is not a weakly prime, because it can be changed into another prime (1291819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645908 + 645909.

It is an arithmetic number, because the mean of its divisors is an integer number (645909).

2^1291817 is an apocalyptic number.

It is an amenable number.

1291817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291817 is an equidigital number, since it uses as much as digits as its factorization.

1291817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 29.

The square root of 1291817 is about 1136.5812773401. The cubic root of 1291817 is about 108.9098095225.

The spelling of 1291817 in words is "one million, two hundred ninety-one thousand, eight hundred seventeen".