211987 has 4 divisors (see below), whose sum is σ = 215640. Its totient is φ = 208336.

The previous prime is 211979. The next prime is 211997. The reversal of 211987 is 789112.

211987 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.

It is a cyclic number.

It is not a de Polignac number, because 211987 - 2³ = 211979 is a prime.

It is a Duffinian number.

211987 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (211927) 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, 1738 + ... + 1855.

It is an arithmetic number, because the mean of its divisors is an integer number (53910).

2²¹¹⁹⁸⁷ is an apocalyptic number.

211987 is a deficient number, since it is larger than the sum of its proper divisors (3653).

211987 is an equidigital number, since it uses as much as digits as its factorization.

211987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3652.

The product of its digits is 1008, while the sum is 28.

The square root of 211987 is about 460.4204600145. The cubic root of 211987 is about 59.6261007551.

The spelling of 211987 in words is "two hundred eleven thousand, nine hundred eighty-seven".