2091611681 has 2 divisors, whose sum is σ = 2091611682. Its totient is φ = 2091611680.

The previous prime is 2091611659. The next prime is 2091611801. The reversal of 2091611681 is 1861161902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2017806400 + 73805281 = 44920^2 + 8591^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2091611681 is a prime.

It is a super-2 number, since 2×2091611681² = 8749678848191291522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2091611611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1045805840 + 1045805841.

It is an arithmetic number, because the mean of its divisors is an integer number (1045805841).

Almost surely, 2^2091611681 is an apocalyptic number.

It is an amenable number.

2091611681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2091611681 is an equidigital number, since it uses as much as digits as its factorization.

2091611681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 2091611681 is about 45734.1413060309. The cubic root of 2091611681 is about 1278.8718251478.

The spelling of 2091611681 in words is "two billion, ninety-one million, six hundred eleven thousand, six hundred eighty-one".