90820 has 24 divisors (see below), whose sum is σ = 201600. Its totient is φ = 34272.

The previous prime is 90803. The next prime is 90821. The reversal of 90820 is 2809.

90820 is nontrivially palindromic in base 14.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261 + ... + 499.

It is an arithmetic number, because the mean of its divisors is an integer number (8400).

2⁹⁰⁸²⁰ 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 90820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100800).

90820 is an abundant number, since it is smaller than the sum of its proper divisors (110780).

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

90820 is a wasteful number, since it uses less digits than its factorization.

90820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 90820 is about 301.3635678047. The cubic root of 90820 is about 44.9497381206.

The spelling of 90820 in words is "ninety thousand, eight hundred twenty".