2101691 has 4 divisors (see below), whose sum is σ = 2104872. Its totient is φ = 2098512.

The previous prime is 2101681. The next prime is 2101703. The reversal of 2101691 is 1961012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2101691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2101621) 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, 185 + ... + 2058.

It is an arithmetic number, because the mean of its divisors is an integer number (526218).

2^2101691 is an apocalyptic number.

2101691 is a deficient number, since it is larger than the sum of its proper divisors (3181).

2101691 is an equidigital number, since it uses as much as digits as its factorization.

2101691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3180.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 2101691 is about 1449.7210076425. The cubic root of 2101691 is about 128.0922796478.

The spelling of 2101691 in words is "two million, one hundred one thousand, six hundred ninety-one".