6520818217 has 8 divisors (see below), whose sum is σ = 6550460840. Its totient is φ = 6491197440.

The previous prime is 6520818209. The next prime is 6520818253. The reversal of 6520818217 is 7128180256.

It can be written as a sum of positive squares in 4 ways, for example, as 1334513961 + 5186304256 = 36531^2 + 72016^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6520818217 - 2³ = 6520818209 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6520818217.

It is not an unprimeable number, because it can be changed into a prime (6520818917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 991813 + ... + 998365.

It is an arithmetic number, because the mean of its divisors is an integer number (818807605).

Almost surely, 2^6520818217 is an apocalyptic number.

It is an amenable number.

6520818217 is a deficient number, since it is larger than the sum of its proper divisors (29642623).

6520818217 is a wasteful number, since it uses less digits than its factorization.

6520818217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10923.

The product of its (nonzero) digits is 53760, while the sum is 40.

The square root of 6520818217 is about 80751.5833714733. The cubic root of 6520818217 is about 1868.2458711627.

The spelling of 6520818217 in words is "six billion, five hundred twenty million, eight hundred eighteen thousand, two hundred seventeen".