2543821 has 4 divisors (see below), whose sum is σ = 2907232. Its totient is φ = 2180412.

The previous prime is 2543813. The next prime is 2543833. The reversal of 2543821 is 1283452.

2543821 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 a cyclic number.

It is not a de Polignac number, because 2543821 - 2³ = 2543813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2543221) 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, 181695 + ... + 181708.

It is an arithmetic number, because the mean of its divisors is an integer number (726808).

2^2543821 is an apocalyptic number.

It is an amenable number.

2543821 is a deficient number, since it is larger than the sum of its proper divisors (363411).

2543821 is an equidigital number, since it uses as much as digits as its factorization.

2543821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363410.

The product of its digits is 1920, while the sum is 25.

The square root of 2543821 is about 1594.9360488747. The cubic root of 2543821 is about 136.5092821088.

It can be divided in two parts, 2543 and 821, that added together give a square (3364 = 58²).

The spelling of 2543821 in words is "two million, five hundred forty-three thousand, eight hundred twenty-one".