109999 has 4 divisors (see below), whose sum is σ = 110664. Its totient is φ = 109336.

The previous prime is 109987. The next prime is 110017. The reversal of 109999 is 999901.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 109999 - 2¹¹ = 107951 is a prime.

It is a Duffinian number.

109999 is a modest number, since divided by 999 gives 109 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (109919) 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, 144 + ... + 490.

It is an arithmetic number, because the mean of its divisors is an integer number (27666).

2¹⁰⁹⁹⁹⁹ is an apocalyptic number.

109999 is a deficient number, since it is larger than the sum of its proper divisors (665).

109999 is an equidigital number, since it uses as much as digits as its factorization.

109999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664.

The product of its (nonzero) digits is 6561, while the sum is 37.

The square root of 109999 is about 331.6609714754. The cubic root of 109999 is about 47.9140533756.

It can be divided in two parts, 1099 and 99, that multiplied together give a palindrome (108801).

The spelling of 109999 in words is "one hundred nine thousand, nine hundred ninety-nine".