6531320209 has 2 divisors, whose sum is σ = 6531320210. Its totient is φ = 6531320208.

The previous prime is 6531320177. The next prime is 6531320239. The reversal of 6531320209 is 9020231356.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3347201025 + 3184119184 = 57855^2 + 56428^2 .

It is a cyclic number.

It is not a de Polignac number, because 6531320209 - 2⁵ = 6531320177 is a prime.

It is not a weakly prime, because it can be changed into another prime (6531320239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3265660104 + 3265660105.

It is an arithmetic number, because the mean of its divisors is an integer number (3265660105).

Almost surely, 2^6531320209 is an apocalyptic number.

It is an amenable number.

6531320209 is a deficient number, since it is larger than the sum of its proper divisors (1).

6531320209 is an equidigital number, since it uses as much as digits as its factorization.

6531320209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 31.

The square root of 6531320209 is about 80816.5837498715. The cubic root of 6531320209 is about 1869.2482903330.

The spelling of 6531320209 in words is "six billion, five hundred thirty-one million, three hundred twenty thousand, two hundred nine".