6681918049 has 9 divisors (see below), whose sum is σ = 6844525779. Its totient is φ = 6523091400.

The previous prime is 6681918031. The next prime is 6681918083. The reversal of 6681918049 is 9408191866.

The square root of 6681918049 is 81743.

It is a perfect power (a square), and thus also a powerful number.

6681918049 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 557290449 + 6124627600 = 23607^2 + 78260^2 .

It is a de Polignac number, because none of the positive numbers 2^k-6681918049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6681917987 and 6681918005.

It is not an unprimeable number, because it can be changed into a prime (6681918149) 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 in 8 ways as a sum of consecutive naturals, for example, 3513999 + ... + 3515899.

Almost surely, 2^6681918049 is an apocalyptic number.

6681918049 is the 81743-rd square number.

6681918049 is the 40872-nd centered octagonal number.

It is an amenable number.

6681918049 is a deficient number, since it is larger than the sum of its proper divisors (162607730).

6681918049 is an frugal number, since it uses more digits than its factorization.

6681918049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3888 (or 1944 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 52.

The cubic root of 6681918049 is about 1883.5061747307.

The spelling of 6681918049 in words is "six billion, six hundred eighty-one million, nine hundred eighteen thousand, forty-nine".