99855 has 24 divisors (see below), whose sum is σ = 198432. Its totient is φ = 45504.

The previous prime is 99839. The next prime is 99859. The reversal of 99855 is 55899.

It is a Cunningham number, because it is equal to 316²-1.

It is not a de Polignac number, because 99855 - 2⁴ = 99839 is a prime.

99855 is a lucky number.

It is a nialpdrome in base 10.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99859) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 157 + ... + 473.

It is an arithmetic number, because the mean of its divisors is an integer number (8268).

2⁹⁹⁸⁵⁵ is an apocalyptic number.

99855 is a deficient number, since it is larger than the sum of its proper divisors (98577).

99855 is a wasteful number, since it uses less digits than its factorization.

99855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 332 counting only the distinct ones).

The product of its digits is 16200, while the sum is 36.

The square root of 99855 is about 315.9984177176. The cubic root of 99855 is about 46.3934431381.

Subtracting from 99855 its reverse (55899), we obtain a triangular number (43956 = T₂₉₆).

The spelling of 99855 in words is "ninety-nine thousand, eight hundred fifty-five".