6817775480221 has 2 divisors, whose sum is σ = 6817775480222. Its totient is φ = 6817775480220.

The previous prime is 6817775480141. The next prime is 6817775480239. The reversal of 6817775480221 is 1220845777186.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6349084628121 + 468690852100 = 2519739^2 + 684610^2 .

It is a cyclic number.

It is not a de Polignac number, because 6817775480221 - 2²⁹ = 6817238609309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6817775480261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3408887740110 + 3408887740111.

It is an arithmetic number, because the mean of its divisors is an integer number (3408887740111).

Almost surely, 2^{6817775480221} is an apocalyptic number.

It is an amenable number.

6817775480221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6817775480221 is an equidigital number, since it uses as much as digits as its factorization.

6817775480221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10536960, while the sum is 58.

The spelling of 6817775480221 in words is "six trillion, eight hundred seventeen billion, seven hundred seventy-five million, four hundred eighty thousand, two hundred twenty-one".