6637772671681 has 2 divisors, whose sum is σ = 6637772671682. Its totient is φ = 6637772671680.

The previous prime is 6637772671679. The next prime is 6637772671741. The reversal of 6637772671681 is 1861762777366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3838562600625 + 2799210071056 = 1959225^2 + 1673084^2 .

It is a cyclic number.

It is not a de Polignac number, because 6637772671681 - 2¹ = 6637772671679 is a prime.

It is a super-2 number, since 2×6637772671681² (a number of 26 digits) contains 22 as substring.

Together with 6637772671679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (6637772671381) 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, 3318886335840 + 3318886335841.

It is an arithmetic number, because the mean of its divisors is an integer number (3318886335841).

Almost surely, 2^{6637772671681} is an apocalyptic number.

It is an amenable number.

6637772671681 is a deficient number, since it is larger than the sum of its proper divisors (1).

6637772671681 is an equidigital number, since it uses as much as digits as its factorization.

6637772671681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 149361408, while the sum is 67.

The spelling of 6637772671681 in words is "six trillion, six hundred thirty-seven billion, seven hundred seventy-two million, six hundred seventy-one thousand, six hundred eighty-one".