6660457681 has 2 divisors, whose sum is σ = 6660457682. Its totient is φ = 6660457680.

The previous prime is 6660457679. The next prime is 6660457697. The reversal of 6660457681 is 1867540666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3554067456 + 3106390225 = 59616^2 + 55735^2 .

It is a cyclic number.

It is not a de Polignac number, because 6660457681 - 2¹ = 6660457679 is a prime.

It is a super-2 number, since 2×6660457681² = 88723393040783795522, which contains 22 as substring.

Together with 6660457679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (6660457651) 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 as a sum of consecutive naturals, namely, 3330228840 + 3330228841.

It is an arithmetic number, because the mean of its divisors is an integer number (3330228841).

Almost surely, 2^6660457681 is an apocalyptic number.

It is an amenable number.

6660457681 is a deficient number, since it is larger than the sum of its proper divisors (1).

6660457681 is an equidigital number, since it uses as much as digits as its factorization.

6660457681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1451520, while the sum is 49.

The square root of 6660457681 is about 81611.6271189345. The cubic root of 6660457681 is about 1881.4875883549.

The spelling of 6660457681 in words is "six billion, six hundred sixty million, four hundred fifty-seven thousand, six hundred eighty-one".