2281821 has 4 divisors (see below), whose sum is σ = 3042432. Its totient is φ = 1521212.

The previous prime is 2281813. The next prime is 2281823. The reversal of 2281821 is 1281822.

2281821 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 2281821 - 2³ = 2281813 is a prime.

It is a D-number.

2281821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 2281791 and 2281800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2281823) 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, 380301 + ... + 380306.

It is an arithmetic number, because the mean of its divisors is an integer number (760608).

2^2281821 is an apocalyptic number.

It is an amenable number.

2281821 is a deficient number, since it is larger than the sum of its proper divisors (760611).

2281821 is an equidigital number, since it uses as much as digits as its factorization.

2281821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760610.

The product of its digits is 512, while the sum is 24.

The square root of 2281821 is about 1510.5697600574. The cubic root of 2281821 is about 131.6519180902.

Subtracting from 2281821 its reverse (1281822), we obtain a palindrome (999999).

The spelling of 2281821 in words is "two million, two hundred eighty-one thousand, eight hundred twenty-one".