211191 has 16 divisors (see below), whose sum is σ = 308448. Its totient is φ = 128000.

The previous prime is 211187. The next prime is 211193. The reversal of 211191 is 191112.

It is a 10-Lehmer number, since φ(211191) divides (211191-1)¹⁰.

It is a cyclic number.

It is not a de Polignac number, because 211191 - 2² = 211187 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 211191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211193) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2041 + ... + 2141.

It is an arithmetic number, because the mean of its divisors is an integer number (19278).

2²¹¹¹⁹¹ is an apocalyptic number.

211191 is the 246-th nonagonal number.

211191 is a deficient number, since it is larger than the sum of its proper divisors (97257).

211191 is a wasteful number, since it uses less digits than its factorization.

211191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162.

The product of its digits is 18, while the sum is 15.

The square root of 211191 is about 459.5552197506. Note that the first 3 decimals coincide. The cubic root of 211191 is about 59.5513761939.

The spelling of 211191 in words is "two hundred eleven thousand, one hundred ninety-one".