2840821 has 4 divisors (see below), whose sum is σ = 2901312. Its totient is φ = 2780332.

The previous prime is 2840801. The next prime is 2840857. The reversal of 2840821 is 1280482.

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 not a de Polignac number, because 2840821 - 2¹³ = 2832629 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 (2840801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30175 + ... + 30268.

It is an arithmetic number, because the mean of its divisors is an integer number (725328).

2^2840821 is an apocalyptic number.

It is an amenable number.

2840821 is a deficient number, since it is larger than the sum of its proper divisors (60491).

2840821 is an equidigital number, since it uses as much as digits as its factorization.

2840821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60490.

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 2840821 is about 1685.4735239689. The cubic root of 2840821 is about 141.6276198423.

The spelling of 2840821 in words is "two million, eight hundred forty thousand, eight hundred twenty-one".