201816 has 24 divisors (see below), whose sum is σ = 546780. Its totient is φ = 67248.

The previous prime is 201809. The next prime is 201821. The reversal of 201816 is 618102.

It is a tau number, because it is divible by the number of its divisors (24).

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1330 + ... + 1473.

2²⁰¹⁸¹⁶ is an apocalyptic number.

It is an amenable number.

201816 is an abundant number, since it is smaller than the sum of its proper divisors (344964).

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

201816 is a wasteful number, since it uses less digits than its factorization.

201816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2815 (or 2808 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 201816 is about 449.2393571360. The cubic root of 201816 is about 58.6568222692.

Adding to 201816 its reverse (618102), we get a palindrome (819918).

The spelling of 201816 in words is "two hundred one thousand, eight hundred sixteen".