20881 has 8 divisors (see below), whose sum is σ = 25280. Its totient is φ = 16848.

The previous prime is 20879. The next prime is 20887. The reversal of 20881 is 18802.

It is a happy number.

20881 is nontrivially palindromic in base 12.

20881 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20881 - 2¹ = 20879 is a prime.

It is a super-2 number, since 2×20881² = 872032322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is the 145-th Hogben number.

It is a Duffinian number.

20881 is an undulating number in base 12.

It is not an unprimeable number, because it can be changed into a prime (20887) by changing a digit.

It is a nontrivial repunit in base 144.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55 + ... + 211.

It is an arithmetic number, because the mean of its divisors is an integer number (3160).

2²⁰⁸⁸¹ is an apocalyptic number.

It is an amenable number.

20881 is a deficient number, since it is larger than the sum of its proper divisors (4399).

20881 is a wasteful number, since it uses less digits than its factorization.

20881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 20881 is about 144.5025951324. The cubic root of 20881 is about 27.5370300048.

It can be divided in two parts, 208 and 81, that added together give a square (289 = 17²).

The spelling of 20881 in words is "twenty thousand, eight hundred eighty-one".