87209 has 4 divisors (see below), whose sum is σ = 89604. Its totient is φ = 84816.

The previous prime is 87187. The next prime is 87211. The reversal of 87209 is 90278.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90278 = 2 ⋅45139.

It can be written as a sum of positive squares in 2 ways, for example, as 48400 + 38809 = 220^2 + 197^2 .

It is a cyclic number.

It is not a de Polignac number, because 87209 - 2¹⁶ = 21673 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87299) 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, 1142 + ... + 1215.

It is an arithmetic number, because the mean of its divisors is an integer number (22401).

2⁸⁷²⁰⁹ is an apocalyptic number.

It is an amenable number.

87209 is a deficient number, since it is larger than the sum of its proper divisors (2395).

87209 is a wasteful number, since it uses less digits than its factorization.

87209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2394.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 87209 is about 295.3116997344. The cubic root of 87209 is about 44.3459301771.

The spelling of 87209 in words is "eighty-seven thousand, two hundred nine".