99920 has 20 divisors (see below), whose sum is σ = 232500. Its totient is φ = 39936.

The previous prime is 99907. The next prime is 99923. The reversal of 99920 is 2999.

It can be written as a sum of positive squares in 2 ways, for example, as 38416 + 61504 = 196^2 + 248^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a nialpdrome in base 10.

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 99920.

It is not an unprimeable number, because it can be changed into a prime (99923) by changing a digit.

99920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545 + ... + 704.

It is an arithmetic number, because the mean of its divisors is an integer number (11625).

2⁹⁹⁹²⁰ is an apocalyptic number.

It is an amenable number.

99920 is an abundant number, since it is smaller than the sum of its proper divisors (132580).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116250).

99920 is a wasteful number, since it uses less digits than its factorization.

99920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1262 (or 1256 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 29.

The square root of 99920 is about 316.1012496021. The cubic root of 99920 is about 46.4035074638.

The spelling of 99920 in words is "ninety-nine thousand, nine hundred twenty".