2131909 has 4 divisors (see below), whose sum is σ = 2295916. Its totient is φ = 1967904.

The previous prime is 2131907. The next prime is 2131937. The reversal of 2131909 is 9091312.

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 199809 + 1932100 = 447^2 + 1390^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131909 - 2¹ = 2131907 is a prime.

It is a Duffinian number.

2131909 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2131907) 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, 81984 + ... + 82009.

It is an arithmetic number, because the mean of its divisors is an integer number (573979).

2^2131909 is an apocalyptic number.

It is an amenable number.

2131909 is a deficient number, since it is larger than the sum of its proper divisors (164007).

2131909 is a wasteful number, since it uses less digits than its factorization.

2131909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164006.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 2131909 is about 1460.1058180831. The cubic root of 2131909 is about 128.7032620125.

The spelling of 2131909 in words is "two million, one hundred thirty-one thousand, nine hundred nine".