991286117 has 2 divisors, whose sum is σ = 991286118. Its totient is φ = 991286116.

The previous prime is 991286057. The next prime is 991286137. The reversal of 991286117 is 711682199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 942858436 + 48427681 = 30706^2 + 6959^2 .

It is a cyclic number.

It is not a de Polignac number, because 991286117 - 2¹² = 991282021 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991286137) 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, 495643058 + 495643059.

It is an arithmetic number, because the mean of its divisors is an integer number (495643059).

Almost surely, 2^991286117 is an apocalyptic number.

It is an amenable number.

991286117 is a deficient number, since it is larger than the sum of its proper divisors (1).

991286117 is an equidigital number, since it uses as much as digits as its factorization.

991286117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 44.

The square root of 991286117 is about 31484.6965524523. The cubic root of 991286117 is about 997.0868943894.

The spelling of 991286117 in words is "nine hundred ninety-one million, two hundred eighty-six thousand, one hundred seventeen".