2101209 has 16 divisors (see below), whose sum is σ = 3132864. Its totient is φ = 1241600.

The previous prime is 2101207. The next prime is 2101213. The reversal of 2101209 is 9021012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 2101209 - 2¹ = 2101207 is a prime.

2101209 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2101207) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 577 + ... + 2129.

It is an arithmetic number, because the mean of its divisors is an integer number (195804).

2^2101209 is an apocalyptic number.

It is an amenable number.

2101209 is a deficient number, since it is larger than the sum of its proper divisors (1031655).

2101209 is a wasteful number, since it uses less digits than its factorization.

2101209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 2101209 is about 1449.5547592278. The cubic root of 2101209 is about 128.0824867082.

The spelling of 2101209 in words is "two million, one hundred one thousand, two hundred nine".