87581 has 4 divisors (see below), whose sum is σ = 94332. Its totient is φ = 80832.

The previous prime is 87559. The next prime is 87583. The reversal of 87581 is 18578.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27556 + 60025 = 166^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 87581 - 2⁶ = 87517 is a prime.

It is a super-2 number, since 2×87581² = 15340863122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 87581.

It is not an unprimeable number, because it can be changed into a prime (87583) 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, 3356 + ... + 3381.

It is an arithmetic number, because the mean of its divisors is an integer number (23583).

2⁸⁷⁵⁸¹ is an apocalyptic number.

It is an amenable number.

87581 is a deficient number, since it is larger than the sum of its proper divisors (6751).

87581 is a wasteful number, since it uses less digits than its factorization.

87581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6750.

The product of its digits is 2240, while the sum is 29.

The square root of 87581 is about 295.9408724729. The cubic root of 87581 is about 44.4088949525.

The spelling of 87581 in words is "eighty-seven thousand, five hundred eighty-one".