999111791 has 2 divisors, whose sum is σ = 999111792. Its totient is φ = 999111790.

The previous prime is 999111781. The next prime is 999111793. The reversal of 999111791 is 197111999.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999111791 is a prime.

Together with 999111793, 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 (999111793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499555895 + 499555896.

It is an arithmetic number, because the mean of its divisors is an integer number (499555896).

Almost surely, 2^999111791 is an apocalyptic number.

999111791 is a deficient number, since it is larger than the sum of its proper divisors (1).

999111791 is an equidigital number, since it uses as much as digits as its factorization.

999111791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45927, while the sum is 47.

The square root of 999111791 is about 31608.7296644455. The cubic root of 999111791 is about 999.7038426328.

The spelling of 999111791 in words is "nine hundred ninety-nine million, one hundred eleven thousand, seven hundred ninety-one".