2861209 has 8 divisors (see below), whose sum is σ = 3114440. Its totient is φ = 2612736.

The previous prime is 2861203. The next prime is 2861213. The reversal of 2861209 is 9021682.

It is a happy number.

2861209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 38809 + 2822400 = 197^2 + 1680^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 3-Lehmer number, since φ(2861209) divides (2861209-1)³.

It is a cyclic number.

It is not a de Polignac number, because 2861209 - 2⁷ = 2861081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2861203) 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 7 ways as a sum of consecutive naturals, for example, 127 + ... + 2395.

It is an arithmetic number, because the mean of its divisors is an integer number (389305).

2^2861209 is an apocalyptic number.

It is an amenable number.

2861209 is a deficient number, since it is larger than the sum of its proper divisors (253231).

2861209 is a wasteful number, since it uses less digits than its factorization.

2861209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2379.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 2861209 is about 1691.5108631043. The cubic root of 2861209 is about 141.9656234976.

Subtracting from 2861209 its product of nonzero digits (1728), we obtain a square (2859481 = 1691²).

The spelling of 2861209 in words is "two million, eight hundred sixty-one thousand, two hundred nine".