218813 has 4 divisors (see below), whose sum is σ = 250080. Its totient is φ = 187548.

The previous prime is 218809. The next prime is 218819. The reversal of 218813 is 318812.

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 218813 - 2² = 218809 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218819) 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, 15623 + ... + 15636.

It is an arithmetic number, because the mean of its divisors is an integer number (62520).

2²¹⁸⁸¹³ is an apocalyptic number.

It is an amenable number.

218813 is a deficient number, since it is larger than the sum of its proper divisors (31267).

218813 is an equidigital number, since it uses as much as digits as its factorization.

218813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31266.

The product of its digits is 384, while the sum is 23.

The square root of 218813 is about 467.7745183312. The cubic root of 218813 is about 60.2593403906.

Subtracting 218813 from its reverse (318812), we obtain a palindrome (99999).

The spelling of 218813 in words is "two hundred eighteen thousand, eight hundred thirteen".