2691871891 has 2 divisors, whose sum is σ = 2691871892. Its totient is φ = 2691871890.

The previous prime is 2691871883. The next prime is 2691871921. The reversal of 2691871891 is 1981781962.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2691871891 - 2³ = 2691871883 is a prime.

It is not a weakly prime, because it can be changed into another prime (2691871811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1345935945 + 1345935946.

It is an arithmetic number, because the mean of its divisors is an integer number (1345935946).

Almost surely, 2^2691871891 is an apocalyptic number.

2691871891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2691871891 is an equidigital number, since it uses as much as digits as its factorization.

2691871891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 52.

The square root of 2691871891 is about 51883.2525098417. The cubic root of 2691871891 is about 1391.0779366883.

The spelling of 2691871891 in words is "two billion, six hundred ninety-one million, eight hundred seventy-one thousand, eight hundred ninety-one".