799999999991 has 2 divisors, whose sum is σ = 799999999992. Its totient is φ = 799999999990.

The previous prime is 799999999889. The next prime is 800000000047. The reversal of 799999999991 is 199999999997.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 799999999991 - 2³⁰ = 798926258167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (799999969991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 399999999995 + 399999999996.

It is an arithmetic number, because the mean of its divisors is an integer number (399999999996).

Almost surely, 2^799999999991 is an apocalyptic number.

799999999991 is a deficient number, since it is larger than the sum of its proper divisors (1).

799999999991 is an equidigital number, since it uses as much as digits as its factorization.

799999999991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24407490807, while the sum is 98.

The spelling of 799999999991 in words is "seven hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-one".