6520345201991 has 2 divisors, whose sum is σ = 6520345201992. Its totient is φ = 6520345201990.

The previous prime is 6520345201969. The next prime is 6520345202017. The reversal of 6520345201991 is 1991025430256.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6520345201991 - 2³⁰ = 6519271460167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6520345209991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3260172600995 + 3260172600996.

It is an arithmetic number, because the mean of its divisors is an integer number (3260172600996).

Almost surely, 2^{6520345201991} is an apocalyptic number.

6520345201991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6520345201991 is an equidigital number, since it uses as much as digits as its factorization.

6520345201991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 583200, while the sum is 47.

The spelling of 6520345201991 in words is "six trillion, five hundred twenty billion, three hundred forty-five million, two hundred one thousand, nine hundred ninety-one".