78799999 has 4 divisors (see below), whose sum is σ = 78855040. Its totient is φ = 78744960.

The previous prime is 78799997. The next prime is 78800017. The reversal of 78799999 is 99999787.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78799999 - 2¹ = 78799997 is a prime.

It is a Duffinian number.

78799999 is a modest number, since divided by 9999 gives 7879 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78799993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25314 + ... + 28255.

It is an arithmetic number, because the mean of its divisors is an integer number (19713760).

Almost surely, 2^78799999 is an apocalyptic number.

78799999 is a deficient number, since it is larger than the sum of its proper divisors (55041).

78799999 is a wasteful number, since it uses less digits than its factorization.

78799999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55040.

The product of its digits is 23147208, while the sum is 67.

The square root of 78799999 is about 8876.9363521431. The cubic root of 78799999 is about 428.7216386536.

The spelling of 78799999 in words is "seventy-eight million, seven hundred ninety-nine thousand, nine hundred ninety-nine".