2181943 has 4 divisors (see below), whose sum is σ = 2190888. Its totient is φ = 2173000.

The previous prime is 2181937. The next prime is 2181947. The reversal of 2181943 is 3491812.

It is a happy number.

2181943 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 a de Polignac number, because none of the positive numbers 2^k-2181943 is a prime.

It is a Duffinian number.

2181943 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4096 + ... + 4597.

It is an arithmetic number, because the mean of its divisors is an integer number (547722).

2^2181943 is an apocalyptic number.

2181943 is a deficient number, since it is larger than the sum of its proper divisors (8945).

2181943 is an equidigital number, since it uses as much as digits as its factorization.

2181943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8944.

The product of its digits is 1728, while the sum is 28.

The square root of 2181943 is about 1477.1401423020. The cubic root of 2181943 is about 129.7023367068.

The spelling of 2181943 in words is "two million, one hundred eighty-one thousand, nine hundred forty-three".