90810 has 24 divisors (see below), whose sum is σ = 236340. Its totient is φ = 24192.

The previous prime is 90803. The next prime is 90821. The reversal of 90810 is 1809.

It can be written as a sum of positive squares in 2 ways, for example, as 88209 + 2601 = 297^2 + 51^2 .

It is a super-2 number, since 2×90810² = 16492912200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

90810 is a modest number, since divided by 810 gives 90 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 415 + ... + 594.

2⁹⁰⁸¹⁰ is an apocalyptic number.

90810 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

90810 is an abundant number, since it is smaller than the sum of its proper divisors (145530).

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 (118170).

90810 is a wasteful number, since it uses less digits than its factorization.

90810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1022 (or 1019 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 90810 is about 301.3469760923. The cubic root of 90810 is about 44.9480882862.

It can be divided in two parts, 90 and 810, that multiplied together give a square (72900 = 270²).

The spelling of 90810 in words is "ninety thousand, eight hundred ten".