6681918149 has 2 divisors, whose sum is σ = 6681918150. Its totient is φ = 6681918148.

The previous prime is 6681918127. The next prime is 6681918167. The reversal of 6681918149 is 9418191866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6681918049 + 100 = 81743^2 + 10^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6681918149 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6681918149.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6681914149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3340959074 + 3340959075.

It is an arithmetic number, because the mean of its divisors is an integer number (3340959075).

Almost surely, 2^6681918149 is an apocalyptic number.

It is an amenable number.

6681918149 is a deficient number, since it is larger than the sum of its proper divisors (1).

6681918149 is an equidigital number, since it uses as much as digits as its factorization.

6681918149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 53.

The square root of 6681918149 is about 81743.0006116732. Note that the first 3 decimals coincide. The cubic root of 6681918149 is about 1883.5061841267.

The spelling of 6681918149 in words is "six billion, six hundred eighty-one million, nine hundred eighteen thousand, one hundred forty-nine".