99820 has 48 divisors (see below), whose sum is σ = 258048. Its totient is φ = 31680.

The previous prime is 99817. The next prime is 99823. The reversal of 99820 is 2899.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (99817) and next prime (99823).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (99823) 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, 3205 + ... + 3235.

It is an arithmetic number, because the mean of its divisors is an integer number (5376).

2⁹⁹⁸²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129024).

99820 is an abundant number, since it is smaller than the sum of its proper divisors (158228).

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

99820 is a wasteful number, since it uses less digits than its factorization.

99820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 99820 is about 315.9430328398. The cubic root of 99820 is about 46.3880220767.

It can be divided in two parts, 99 and 820, that added together give a palindrome (919).

The spelling of 99820 in words is "ninety-nine thousand, eight hundred twenty".