999918 has 16 divisors (see below), whose sum is σ = 2222160. Its totient is φ = 333288.

The previous prime is 999917. The next prime is 999931. The reversal of 999918 is 819999.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 999918.

It is not an unprimeable number, because it can be changed into a prime (999917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9205 + ... + 9312.

It is an arithmetic number, because the mean of its divisors is an integer number (138885).

2⁹⁹⁹⁹¹⁸ is an apocalyptic number.

999918 is an abundant number, since it is smaller than the sum of its proper divisors (1222242).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999918 is a wasteful number, since it uses less digits than its factorization.

999918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18528 (or 18522 counting only the distinct ones).

The product of its digits is 52488, while the sum is 45.

The square root of 999918 is about 999.9589991595. The cubic root of 999918 is about 99.9972665920.

It can be divided in two parts, 99991 and 8, that added together give a palindrome (99999).

The spelling of 999918 in words is "nine hundred ninety-nine thousand, nine hundred eighteen".