797779991 has 2 divisors, whose sum is σ = 797779992. Its totient is φ = 797779990.

The previous prime is 797779987. The next prime is 797780017. The reversal of 797779991 is 199977797.

797779991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (199977797) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 797779991 - 2² = 797779987 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 (797779951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 398889995 + 398889996.

It is an arithmetic number, because the mean of its divisors is an integer number (398889996).

Almost surely, 2^797779991 is an apocalyptic number.

797779991 is a deficient number, since it is larger than the sum of its proper divisors (1).

797779991 is an equidigital number, since it uses as much as digits as its factorization.

797779991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15752961, while the sum is 65.

The square root of 797779991 is about 28244.9993981236. Note that the first 3 decimals coincide. The cubic root of 797779991 is about 927.4582737820.

The spelling of 797779991 in words is "seven hundred ninety-seven million, seven hundred seventy-nine thousand, nine hundred ninety-one".