78599999 has 4 divisors (see below), whose sum is σ = 78618336. Its totient is φ = 78581664.

The previous prime is 78599971. The next prime is 78600019. The reversal of 78599999 is 99999587.

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 78599999 - 2¹² = 78595903 is a prime.

It is a Duffinian number.

78599999 is a modest number, since divided by 9999 gives 7859 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78599909) 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, 1082 + ... + 12584.

It is an arithmetic number, because the mean of its divisors is an integer number (19654584).

Almost surely, 2^78599999 is an apocalyptic number.

78599999 is a deficient number, since it is larger than the sum of its proper divisors (18337).

78599999 is a wasteful number, since it uses less digits than its factorization.

78599999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18336.

The product of its digits is 16533720, while the sum is 65.

The square root of 78599999 is about 8865.6640473232. The cubic root of 78599999 is about 428.3586226933.

The spelling of 78599999 in words is "seventy-eight million, five hundred ninety-nine thousand, nine hundred ninety-nine".