211081 has 6 divisors (see below), whose sum is σ = 228750. Its totient is φ = 194688.

The previous prime is 211073. The next prime is 211093. The reversal of 211081 is 180112.

It can be written as a sum of positive squares in 3 ways, for example, as 400 + 210681 = 20^2 + 459^2 .

It is not a de Polignac number, because 211081 - 2³ = 211073 is a prime.

It is a super-3 number, since 3×211081³ = 28214261269933323, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a plaindrome in base 16.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 456 + ... + 793.

It is an arithmetic number, because the mean of its divisors is an integer number (38125).

2²¹¹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

211081 is a deficient number, since it is larger than the sum of its proper divisors (17669).

211081 is a wasteful number, since it uses less digits than its factorization.

211081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1275 (or 1262 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 211081 is about 459.4355232239. The cubic root of 211081 is about 59.5410351771.

Adding to 211081 its reverse (180112), we get a palindrome (391193).

The spelling of 211081 in words is "two hundred eleven thousand, eighty-one".