6680006721 has 6 divisors (see below), whose sum is σ = 9648898610. Its totient is φ = 4453337808.

The previous prime is 6680006689. The next prime is 6680006737. The reversal of 6680006721 is 1276000866.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 4193987121 + 2486019600 = 64761^2 + 49860^2 .

It is not a de Polignac number, because 6680006721 - 2⁵ = 6680006689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6680006521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 371111476 + ... + 371111493.

Almost surely, 2^6680006721 is an apocalyptic number.

It is an amenable number.

6680006721 is a deficient number, since it is larger than the sum of its proper divisors (2968891889).

6680006721 is a wasteful number, since it uses less digits than its factorization.

6680006721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742222975 (or 742222972 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 6680006721 is about 81731.3080832553. The cubic root of 6680006721 is about 1883.3265685472.

The spelling of 6680006721 in words is "six billion, six hundred eighty million, six thousand, seven hundred twenty-one".