20087 has 4 divisors (see below), whose sum is σ = 20520. Its totient is φ = 19656.

The previous prime is 20071. The next prime is 20089. The reversal of 20087 is 78002.

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

It is a cyclic number.

It is not a de Polignac number, because 20087 - 2⁴ = 20071 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 (20089) 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, 137 + ... + 242.

It is an arithmetic number, because the mean of its divisors is an integer number (5130).

2²⁰⁰⁸⁷ is an apocalyptic number.

20087 is a deficient number, since it is larger than the sum of its proper divisors (433).

20087 is an equidigital number, since it uses as much as digits as its factorization.

20087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 20087 is about 141.7286139070. The cubic root of 20087 is about 27.1834782883.

Adding to 20087 its reverse (78002), we get a palindrome (98089).

The spelling of 20087 in words is "twenty thousand, eighty-seven".