6468206521681 has 2 divisors, whose sum is σ = 6468206521682. Its totient is φ = 6468206521680.

The previous prime is 6468206521657. The next prime is 6468206521691. The reversal of 6468206521681 is 1861256028646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4598382739456 + 1869823782225 = 2144384^2 + 1367415^2 .

It is a cyclic number.

It is not a de Polignac number, because 6468206521681 - 2¹⁷ = 6468206390609 is a prime.

It is a super-2 number, since 2×6468206521681² (a number of 26 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6468206521631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3234103260840 + 3234103260841.

It is an arithmetic number, because the mean of its divisors is an integer number (3234103260841).

Almost surely, 2^{6468206521681} is an apocalyptic number.

It is an amenable number.

6468206521681 is a deficient number, since it is larger than the sum of its proper divisors (1).

6468206521681 is an equidigital number, since it uses as much as digits as its factorization.

6468206521681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6635520, while the sum is 55.

The spelling of 6468206521681 in words is "six trillion, four hundred sixty-eight billion, two hundred six million, five hundred twenty-one thousand, six hundred eighty-one".