78899999 has 4 divisors (see below), whose sum is σ = 79313280. Its totient is φ = 78486720.

The previous prime is 78899993. The next prime is 78900001. The reversal of 78899999 is 99999887.

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 78899999 - 2⁴ = 78899983 is a prime.

It is a Duffinian number.

78899999 is a modest number, since divided by 9999 gives 7889 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78899993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206354 + ... + 206735.

It is an arithmetic number, because the mean of its divisors is an integer number (19828320).

Almost surely, 2^78899999 is an apocalyptic number.

78899999 is a deficient number, since it is larger than the sum of its proper divisors (413281).

78899999 is a wasteful number, since it uses less digits than its factorization.

78899999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 413280.

The product of its digits is 26453952, while the sum is 68.

The square root of 78899999 is about 8882.5671401909. The cubic root of 78899999 is about 428.9029163259.

The spelling of 78899999 in words is "seventy-eight million, eight hundred ninety-nine thousand, nine hundred ninety-nine".