2181686851 has 2 divisors, whose sum is σ = 2181686852. Its totient is φ = 2181686850.

The previous prime is 2181686809. The next prime is 2181686863. The reversal of 2181686851 is 1586861812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2181686851 - 2²³ = 2173298243 is a prime.

It is not a weakly prime, because it can be changed into another prime (2181486851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090843425 + 1090843426.

It is an arithmetic number, because the mean of its divisors is an integer number (1090843426).

Almost surely, 2^2181686851 is an apocalyptic number.

2181686851 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181686851 is an equidigital number, since it uses as much as digits as its factorization.

2181686851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 184320, while the sum is 46.

The square root of 2181686851 is about 46708.5308161154. The cubic root of 2181686851 is about 1296.9726104349.

The spelling of 2181686851 in words is "two billion, one hundred eighty-one million, six hundred eighty-six thousand, eight hundred fifty-one".