799991 has 2 divisors, whose sum is σ = 799992. Its totient is φ = 799990.

The previous prime is 799979. The next prime is 799993. The reversal of 799991 is 199997.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 799991 - 2¹⁸ = 537847 is a prime.

Together with 799993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 799991.

It is not a weakly prime, because it can be changed into another prime (799993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 399995 + 399996.

It is an arithmetic number, because the mean of its divisors is an integer number (399996).

2⁷⁹⁹⁹⁹¹ is an apocalyptic number.

799991 is a deficient number, since it is larger than the sum of its proper divisors (1).

799991 is an equidigital number, since it uses as much as digits as its factorization.

799991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45927, while the sum is 44.

The square root of 799991 is about 894.4221598328. The cubic root of 799991 is about 92.8314285518.

The spelling of 799991 in words is "seven hundred ninety-nine thousand, nine hundred ninety-one".