1991426159 has 2 divisors, whose sum is σ = 1991426160. Its totient is φ = 1991426158.

The previous prime is 1991426137. The next prime is 1991426161. The reversal of 1991426159 is 9516241991.

It is a strong prime.

It is an emirp because it is prime and its reverse (9516241991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1991426159 - 2²⁰ = 1990377583 is a prime.

Together with 1991426161, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1991426659) 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, 995713079 + 995713080.

It is an arithmetic number, because the mean of its divisors is an integer number (995713080).

Almost surely, 2^1991426159 is an apocalyptic number.

1991426159 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991426159 is an equidigital number, since it uses as much as digits as its factorization.

1991426159 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 174960, while the sum is 47.

The square root of 1991426159 is about 44625.3981382800. The cubic root of 1991426159 is about 1258.1180772427.

The spelling of 1991426159 in words is "one billion, nine hundred ninety-one million, four hundred twenty-six thousand, one hundred fifty-nine".