211491 has 20 divisors (see below), whose sum is σ = 362032. Its totient is φ = 120528.

The previous prime is 211469. The next prime is 211493. The reversal of 211491 is 194112.

211491 is nontrivially palindromic in base 13.

211491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 211491 - 2⁶ = 211427 is a prime.

It is a Duffinian number.

211491 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211493) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 381 + ... + 753.

2²¹¹⁴⁹¹ is an apocalyptic number.

211491 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

211491 is a deficient number, since it is larger than the sum of its proper divisors (150541).

211491 is an equidigital number, since it uses as much as digits as its factorization.

211491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392 (or 383 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

The square root of 211491 is about 459.8815064775. The cubic root of 211491 is about 59.5795607285.

The spelling of 211491 in words is "two hundred eleven thousand, four hundred ninety-one".