6560720521 has 4 divisors (see below), whose sum is σ = 6561785412. Its totient is φ = 6559655632.

The previous prime is 6560720503. The next prime is 6560720533. The reversal of 6560720521 is 1250270656.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 779247225 + 5781473296 = 27915^2 + 76036^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6560720521 is a prime.

It is a super-2 number, since 2×6560720521² = 86086107509341022882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6560720561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 523150 + ... + 535543.

It is an arithmetic number, because the mean of its divisors is an integer number (1640446353).

Almost surely, 2^6560720521 is an apocalyptic number.

It is an amenable number.

6560720521 is a deficient number, since it is larger than the sum of its proper divisors (1064891).

6560720521 is a wasteful number, since it uses less digits than its factorization.

6560720521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1064890.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 6560720521 is about 80998.2748026154. The cubic root of 6560720521 is about 1872.0488587622.

The spelling of 6560720521 in words is "six billion, five hundred sixty million, seven hundred twenty thousand, five hundred twenty-one".