2131209 has 12 divisors (see below), whose sum is σ = 3150576. Its totient is φ = 1387512.

The previous prime is 2131193. The next prime is 2131223. The reversal of 2131209 is 9021312.

It is a happy number.

It is not a de Polignac number, because 2131209 - 2⁴ = 2131193 is a prime.

2131209 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 2131191 and 2131200.

It is not an unprimeable number, because it can be changed into a prime (2131109) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2367 + ... + 3140.

It is an arithmetic number, because the mean of its divisors is an integer number (262548).

2^2131209 is an apocalyptic number.

It is an amenable number.

2131209 is a deficient number, since it is larger than the sum of its proper divisors (1019367).

2131209 is a wasteful number, since it uses less digits than its factorization.

2131209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5556 (or 5553 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 2131209 is about 1459.8660897493. The cubic root of 2131209 is about 128.6891741464.

The spelling of 2131209 in words is "two million, one hundred thirty-one thousand, two hundred nine".