87809 has 4 divisors (see below), whose sum is σ = 88404. Its totient is φ = 87216.

The previous prime is 87803. The next prime is 87811. The reversal of 87809 is 90878.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 90878 = 2 ⋅45439.

It can be written as a sum of positive squares in 2 ways, for example, as 9409 + 78400 = 97^2 + 280^2 .

It is a cyclic number.

It is not a de Polignac number, because 87809 - 2⁴ = 87793 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87803) 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 3 ways as a sum of consecutive naturals, for example, 119 + ... + 435.

It is an arithmetic number, because the mean of its divisors is an integer number (22101).

2⁸⁷⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

87809 is a deficient number, since it is larger than the sum of its proper divisors (595).

87809 is a wasteful number, since it uses less digits than its factorization.

87809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 87809 is about 296.3258341758. The cubic root of 87809 is about 44.4473981833.

The spelling of 87809 in words is "eighty-seven thousand, eight hundred nine".