99789 has 16 divisors (see below), whose sum is σ = 145920. Its totient is φ = 60480.

The previous prime is 99787. The next prime is 99793. The reversal of 99789 is 98799.

It is a happy number.

It is not a de Polignac number, because 99789 - 2¹ = 99787 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99789.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99787) 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, 2679 + ... + 2715.

It is an arithmetic number, because the mean of its divisors is an integer number (9120).

2⁹⁹⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

99789 is a deficient number, since it is larger than the sum of its proper divisors (46131).

99789 is a wasteful number, since it uses less digits than its factorization.

99789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100.

The product of its digits is 40824, while the sum is 42.

The square root of 99789 is about 315.8939695531. The cubic root of 99789 is about 46.3832195068.

Subtracting from 99789 its reverse (98799), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 99 and 789, that added together give a palindrome (888).

The spelling of 99789 in words is "ninety-nine thousand, seven hundred eighty-nine".