2289821 has 4 divisors (see below), whose sum is σ = 2322144. Its totient is φ = 2257500.

The previous prime is 2289817. The next prime is 2289829. The reversal of 2289821 is 1289822.

2289821 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, and also an emirpimes, since its reverse is a distinct semiprime: 1289822 = 2 ⋅644911.

It is a cyclic number.

It is not a de Polignac number, because 2289821 - 2² = 2289817 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 (2289829) 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, 16055 + ... + 16196.

It is an arithmetic number, because the mean of its divisors is an integer number (580536).

2^2289821 is an apocalyptic number.

It is an amenable number.

2289821 is a deficient number, since it is larger than the sum of its proper divisors (32323).

2289821 is an equidigital number, since it uses as much as digits as its factorization.

2289821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32322.

The product of its digits is 4608, while the sum is 32.

The square root of 2289821 is about 1513.2154506216. The cubic root of 2289821 is about 131.8055946040.

Subtracting from 2289821 its reverse (1289822), we obtain a palindrome (999999).

The spelling of 2289821 in words is "two million, two hundred eighty-nine thousand, eight hundred twenty-one".