90100 has 36 divisors (see below), whose sum is σ = 210924. Its totient is φ = 33280.

The previous prime is 90089. The next prime is 90107. The reversal of 90100 is 109.

It is a happy number.

90100 is a nontrivial binomial coefficient, being equal to C(425, 2).

It can be written as a sum of positive squares in 6 ways, for example, as 1296 + 88804 = 36^2 + 298^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90107) by changing a digit.

90100 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 11 ways as a sum of consecutive naturals, for example, 1674 + ... + 1726.

It is an arithmetic number, because the mean of its divisors is an integer number (5859).

2⁹⁰¹⁰⁰ is an apocalyptic number.

90100 is the 424-th triangular number.

90100 is the 142-nd centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 90100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105462).

90100 is an abundant number, since it is smaller than the sum of its proper divisors (120824).

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

90100 is a wasteful number, since it uses less digits than its factorization.

90100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 9, while the sum is 10.

The square root of 90100 is about 300.1666203961. The cubic root of 90100 is about 44.8306391174.

Adding to 90100 its reverse (109), we get a palindrome (90209).

It can be divided in two parts, 90 and 100, that added together give a triangular number (190 = T₁₉).

The spelling of 90100 in words is "ninety thousand, one hundred".