90809 has 4 divisors (see below), whose sum is σ = 92160. Its totient is φ = 89460.

The previous prime is 90803. The next prime is 90821.

It is a happy number.

90809 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 90809 - 2⁴ = 90793 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 569 + ... + 710.

It is an arithmetic number, because the mean of its divisors is an integer number (23040).

2⁹⁰⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

90809 is a deficient number, since it is larger than the sum of its proper divisors (1351).

90809 is a wasteful number, since it uses less digits than its factorization.

90809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1350.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 90809 is about 301.3453168709. The cubic root of 90809 is about 44.9479232961.

The spelling of 90809 in words is "ninety thousand, eight hundred nine".