778899999 has 16 divisors (see below), whose sum is σ = 1114692192. Its totient is φ = 482024448.

The previous prime is 778899997. The next prime is 778900043. The reversal of 778899999 is 999998877.

It is not a de Polignac number, because 778899999 - 2¹ = 778899997 is a prime.

778899999 is a modest number, since divided by 99999 gives 7788 as remainder.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 778899999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (778899997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100884 + ... + 108329.

It is an arithmetic number, because the mean of its divisors is an integer number (69668262).

Almost surely, 2^778899999 is an apocalyptic number.

778899999 is a deficient number, since it is larger than the sum of its proper divisors (335792193).

778899999 is a wasteful number, since it uses less digits than its factorization.

778899999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209306.

The product of its digits is 185177664, while the sum is 75.

The square root of 778899999 is about 27908.7799625853. The cubic root of 778899999 is about 920.0834828938.

The spelling of 778899999 in words is "seven hundred seventy-eight million, eight hundred ninety-nine thousand, nine hundred ninety-nine".