2661209 has 4 divisors (see below), whose sum is σ = 2673060. Its totient is φ = 2649360.

The previous prime is 2661199. The next prime is 2661221. The reversal of 2661209 is 9021662.

2661209 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.

It can be written as a sum of positive squares in 2 ways, for example, as 1345600 + 1315609 = 1160^2 + 1147^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2661209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2661409) 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, 5582 + ... + 6039.

It is an arithmetic number, because the mean of its divisors is an integer number (668265).

2^2661209 is an apocalyptic number.

It is an amenable number.

2661209 is a deficient number, since it is larger than the sum of its proper divisors (11851).

2661209 is a wasteful number, since it uses less digits than its factorization.

2661209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11850.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 2661209 is about 1631.3212436550. The cubic root of 2661209 is about 138.5775868896.

The spelling of 2661209 in words is "two million, six hundred sixty-one thousand, two hundred nine".