211971 has 4 divisors (see below), whose sum is σ = 282632. Its totient is φ = 141312.

The previous prime is 211969. The next prime is 211979. The reversal of 211971 is 179112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 211971 - 2¹ = 211969 is a prime.

It is a D-number.

It is a Duffinian number.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (211979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35326 + ... + 35331.

It is an arithmetic number, because the mean of its divisors is an integer number (70658).

2²¹¹⁹⁷¹ is an apocalyptic number.

211971 is a deficient number, since it is larger than the sum of its proper divisors (70661).

211971 is an equidigital number, since it uses as much as digits as its factorization.

211971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70660.

The product of its digits is 126, while the sum is 21.

The square root of 211971 is about 460.4030842642. The cubic root of 211971 is about 59.6246005977.

The spelling of 211971 in words is "two hundred eleven thousand, nine hundred seventy-one".