211989 has 4 divisors (see below), whose sum is σ = 282656. Its totient is φ = 141324.

The previous prime is 211979. The next prime is 211997. The reversal of 211989 is 989112.

211989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 211989 - 2¹⁷ = 80917 is a prime.

It is a super-2 number, since 2×211989² = 89878672242, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211949) 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, 35329 + ... + 35334.

It is an arithmetic number, because the mean of its divisors is an integer number (70664).

2²¹¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

211989 is a deficient number, since it is larger than the sum of its proper divisors (70667).

211989 is an equidigital number, since it uses as much as digits as its factorization.

211989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70666.

The product of its digits is 1296, while the sum is 30.

The square root of 211989 is about 460.4226319372. The cubic root of 211989 is about 59.6262882695.

The spelling of 211989 in words is "two hundred eleven thousand, nine hundred eighty-nine".