201818 has 16 divisors (see below), whose sum is σ = 328320. Its totient is φ = 92736.

The previous prime is 201809. The next prime is 201821. The reversal of 201818 is 818102.

201818 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

201818 is a modest number, since divided by 1818 gives 20 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 201818.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1730 + ... + 1842.

It is an arithmetic number, because the mean of its divisors is an integer number (20520).

2²⁰¹⁸¹⁸ is an apocalyptic number.

201818 is a deficient number, since it is larger than the sum of its proper divisors (126502).

201818 is a wasteful number, since it uses less digits than its factorization.

201818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 201818 is about 449.2415831154. The cubic root of 201818 is about 58.6570160319.

The spelling of 201818 in words is "two hundred one thousand, eight hundred eighteen".