78999911 has 2 divisors, whose sum is σ = 78999912. Its totient is φ = 78999910.

The previous prime is 78999889. The next prime is 78999913. The reversal of 78999911 is 11999987.

It is a strong prime.

It is an emirp because it is prime and its reverse (11999987) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78999911 is a prime.

Together with 78999913, 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 (78999913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39499955 + 39499956.

It is an arithmetic number, because the mean of its divisors is an integer number (39499956).

Almost surely, 2^78999911 is an apocalyptic number.

78999911 is a deficient number, since it is larger than the sum of its proper divisors (1).

78999911 is an equidigital number, since it uses as much as digits as its factorization.

78999911 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 53.

The square root of 78999911 is about 8888.1894106730. The cubic root of 78999911 is about 429.0838815697.

The spelling of 78999911 in words is "seventy-eight million, nine hundred ninety-nine thousand, nine hundred eleven".