218881 has 8 divisors (see below), whose sum is σ = 239400. Its totient is φ = 198912.

The previous prime is 218873. The next prime is 218887. The reversal of 218881 is 188812.

It can be written as a sum of positive squares in 4 ways, for example, as 25281 + 193600 = 159^2 + 440^2 .

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 218881 - 2³ = 218873 is a prime.

It is a super-2 number, since 2×218881² = 95817784322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1395 + ... + 1543.

It is an arithmetic number, because the mean of its divisors is an integer number (29925).

2²¹⁸⁸⁸¹ is an apocalyptic number.

It is an amenable number.

218881 is a deficient number, since it is larger than the sum of its proper divisors (20519).

218881 is a wasteful number, since it uses less digits than its factorization.

218881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275.

The product of its digits is 1024, while the sum is 28.

The square root of 218881 is about 467.8471972771. The cubic root of 218881 is about 60.2655819618.

The spelling of 218881 in words is "two hundred eighteen thousand, eight hundred eighty-one".