218861 has 4 divisors (see below), whose sum is σ = 230400. Its totient is φ = 207324.

The previous prime is 218857. The next prime is 218873. The reversal of 218861 is 168812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 218861 - 2² = 218857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 218861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218461) 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, 5741 + ... + 5778.

It is an arithmetic number, because the mean of its divisors is an integer number (57600).

2²¹⁸⁸⁶¹ is an apocalyptic number.

It is an amenable number.

218861 is a deficient number, since it is larger than the sum of its proper divisors (11539).

218861 is a wasteful number, since it uses less digits than its factorization.

218861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11538.

The product of its digits is 768, while the sum is 26.

The square root of 218861 is about 467.8258222886. The cubic root of 218861 is about 60.2637463398.

The spelling of 218861 in words is "two hundred eighteen thousand, eight hundred sixty-one".