211816 has 32 divisors (see below), whose sum is σ = 453600. Its totient is φ = 91840.

The previous prime is 211811. The next prime is 211817. The reversal of 211816 is 618112.

It is a junction number, because it is equal to n+sod(n) for n = 211793 and 211802.

It is not an unprimeable number, because it can be changed into a prime (211811) by changing a digit.

211816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2511 + ... + 2593.

It is an arithmetic number, because the mean of its divisors is an integer number (14175).

2²¹¹⁸¹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 211816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226800).

211816 is an abundant number, since it is smaller than the sum of its proper divisors (241784).

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

211816 is a wasteful number, since it uses less digits than its factorization.

211816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 125 counting only the distinct ones).

The product of its digits is 96, while the sum is 19.

The square root of 211816 is about 460.2347227231. The cubic root of 211816 is about 59.6100639132.

Adding to 211816 its reverse (618112), we get a palindrome (829928).

It can be divided in two parts, 2 and 11816, that multiplied together give a palindrome (23632).

The spelling of 211816 in words is "two hundred eleven thousand, eight hundred sixteen".