2081861 has 2 divisors, whose sum is σ = 2081862. Its totient is φ = 2081860.

The previous prime is 2081851. The next prime is 2081873. The reversal of 2081861 is 1681802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1600225 + 481636 = 1265^2 + 694^2 .

It is a cyclic number.

It is not a de Polignac number, because 2081861 - 2⁶ = 2081797 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2081861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2081801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1040930 + 1040931.

It is an arithmetic number, because the mean of its divisors is an integer number (1040931).

2^2081861 is an apocalyptic number.

It is an amenable number.

2081861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2081861 is an equidigital number, since it uses as much as digits as its factorization.

2081861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 2081861 is about 1442.8655516021. The cubic root of 2081861 is about 127.6881446306.

The spelling of 2081861 in words is "two million, eighty-one thousand, eight hundred sixty-one".