2821209 has 4 divisors (see below), whose sum is σ = 3761616. Its totient is φ = 1880804.

The previous prime is 2821183. The next prime is 2821229. The reversal of 2821209 is 9021282.

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 2821209 - 2¹⁷ = 2690137 is a prime.

It is a D-number.

2821209 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2821229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 470199 + ... + 470204.

It is an arithmetic number, because the mean of its divisors is an integer number (940404).

2^2821209 is an apocalyptic number.

It is an amenable number.

2821209 is a deficient number, since it is larger than the sum of its proper divisors (940407).

2821209 is an equidigital number, since it uses as much as digits as its factorization.

2821209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 940406.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 2821209 is about 1679.6454983121. The cubic root of 2821209 is about 141.3009516762.

The spelling of 2821209 in words is "two million, eight hundred twenty-one thousand, two hundred nine".