6520345209991 has 2 divisors, whose sum is σ = 6520345209992. Its totient is φ = 6520345209990.

The previous prime is 6520345209953. The next prime is 6520345210019. The reversal of 6520345209991 is 1999025430256.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6520345209991 - 2⁹ = 6520345209479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6520345201991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3260172604995 + 3260172604996.

It is an arithmetic number, because the mean of its divisors is an integer number (3260172604996).

Almost surely, 2^{6520345209991} is an apocalyptic number.

6520345209991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6520345209991 is an equidigital number, since it uses as much as digits as its factorization.

6520345209991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5248800, while the sum is 55.

The spelling of 6520345209991 in words is "six trillion, five hundred twenty billion, three hundred forty-five million, two hundred nine thousand, nine hundred ninety-one".