218840 has 16 divisors (see below), whose sum is σ = 492480. Its totient is φ = 87520.

The previous prime is 218839. The next prime is 218843. The reversal of 218840 is 48812.

It is a nialpdrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218843) 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, 2696 + ... + 2775.

It is an arithmetic number, because the mean of its divisors is an integer number (30780).

2²¹⁸⁸⁴⁰ is an apocalyptic number.

218840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218840 is an abundant number, since it is smaller than the sum of its proper divisors (273640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218840 is a wasteful number, since it uses less digits than its factorization.

218840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5482 (or 5478 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 218840 is about 467.8033774996. The cubic root of 218840 is about 60.2618188163.

The spelling of 218840 in words is "two hundred eighteen thousand, eight hundred forty".