126209 has 4 divisors (see below), whose sum is σ = 128340. Its totient is φ = 124080.

The previous prime is 126199. The next prime is 126211. The reversal of 126209 is 902621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902621 = 353 ⋅2557.

It can be written as a sum of positive squares in 2 ways, for example, as 10609 + 115600 = 103^2 + 340^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-126209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (126229) 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, 974 + ... + 1095.

It is an arithmetic number, because the mean of its divisors is an integer number (32085).

2¹²⁶²⁰⁹ is an apocalyptic number.

It is an amenable number.

126209 is a deficient number, since it is larger than the sum of its proper divisors (2131).

126209 is an equidigital number, since it uses as much as digits as its factorization.

126209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2130.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 126209 is about 355.2590604052. The cubic root of 126209 is about 50.1606830659.

The spelling of 126209 in words is "one hundred twenty-six thousand, two hundred nine".