2155209 has 16 divisors (see below), whose sum is σ = 3477888. Its totient is φ = 1158912.

The previous prime is 2155207. The next prime is 2155253. The reversal of 2155209 is 9025512.

It is not a de Polignac number, because 2155209 - 2¹ = 2155207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2155201) 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, 2662 + ... + 3375.

It is an arithmetic number, because the mean of its divisors is an integer number (217368).

2^2155209 is an apocalyptic number.

It is an amenable number.

2155209 is a deficient number, since it is larger than the sum of its proper divisors (1322679).

2155209 is a wasteful number, since it uses less digits than its factorization.

2155209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6064.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 2155209 is about 1468.0630095469. The cubic root of 2155209 is about 129.1704375359.

The spelling of 2155209 in words is "two million, one hundred fifty-five thousand, two hundred nine".