89999 has 16 divisors (see below), whose sum is σ = 118272. Its totient is φ = 66528.

The previous prime is 89989. The next prime is 90001. The reversal of 89999 is 99998.

89999 = T₄₂ + T₄₃ + ... + T₈₄.

89999 = 2³ + 3³ + ... + 24³.

It is a Cunningham number, because it is equal to 300²-1.

It is not a de Polignac number, because 89999 - 2⁴ = 89983 is a prime.

89999 is a modest number, since divided by 999 gives 89 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 (89909) 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, 2072 + ... + 2114.

It is an arithmetic number, because the mean of its divisors is an integer number (7392).

2⁸⁹⁹⁹⁹ is an apocalyptic number.

89999 is a deficient number, since it is larger than the sum of its proper divisors (28273).

89999 is a wasteful number, since it uses less digits than its factorization.

89999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86.

The product of its digits is 52488, while the sum is 44.

The square root of 89999 is about 299.9983333287. The cubic root of 89999 is about 44.8138814870.

Subtracting 89999 from its reverse (99998), we obtain a palindrome (9999).

The spelling of 89999 in words is "eighty-nine thousand, nine hundred ninety-nine".