2131685 has 12 divisors (see below), whose sum is σ = 2627148. Its totient is φ = 1660416.

The previous prime is 2131669. The next prime is 2131687. The reversal of 2131685 is 5861312.

It can be written as a sum of positive squares in 2 ways, for example, as 638401 + 1493284 = 799^2 + 1222^2 .

It is not a de Polignac number, because 2131685 - 2⁴ = 2131669 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2131687) 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, 10949 + ... + 11141.

It is an arithmetic number, because the mean of its divisors is an integer number (218929).

2^2131685 is an apocalyptic number.

It is an amenable number.

2131685 is a deficient number, since it is larger than the sum of its proper divisors (495463).

2131685 is an equidigital number, since it uses as much as digits as its factorization.

2131685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292 (or 245 counting only the distinct ones).

The product of its digits is 1440, while the sum is 26.

The square root of 2131685 is about 1460.0291092989. The cubic root of 2131685 is about 128.6987542309.

Adding to 2131685 its reverse (5861312), we get a palindrome (7992997).

The spelling of 2131685 in words is "two million, one hundred thirty-one thousand, six hundred eighty-five".