2091685 has 4 divisors (see below), whose sum is σ = 2510028. Its totient is φ = 1673344.

The previous prime is 2091671. The next prime is 2091703. The reversal of 2091685 is 5861902.

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 910116 + 1181569 = 954^2 + 1087^2 .

It is a cyclic number.

It is not a de Polignac number, because 2091685 - 2¹⁷ = 1960613 is a prime.

It is a super-2 number, since 2×2091685² = 8750292278450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 209164 + ... + 209173.

It is an arithmetic number, because the mean of its divisors is an integer number (627507).

2^2091685 is an apocalyptic number.

It is an amenable number.

2091685 is a deficient number, since it is larger than the sum of its proper divisors (418343).

2091685 is an equidigital number, since it uses as much as digits as its factorization.

2091685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418342.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 2091685 is about 1446.2658815031. The cubic root of 2091685 is about 127.8886768092. Note that the first 3 decimals are identical.

The spelling of 2091685 in words is "two million, ninety-one thousand, six hundred eighty-five".