6560721 has 6 divisors (see below), whose sum is σ = 9476610. Its totient is φ = 4373808.

The previous prime is 6560717. The next prime is 6560731. The reversal of 6560721 is 1270656.

6560721 is a `hidden beast` number, since 656 + 0 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 3459600 + 3101121 = 1860^2 + 1761^2 .

It is not a de Polignac number, because 6560721 - 2² = 6560717 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (6560731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 364476 + ... + 364493.

It is an arithmetic number, because the mean of its divisors is an integer number (1579435).

Almost surely, 2^6560721 is an apocalyptic number.

It is an amenable number.

6560721 is a deficient number, since it is larger than the sum of its proper divisors (2915889).

6560721 is a wasteful number, since it uses less digits than its factorization.

6560721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728975 (or 728972 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 6560721 is about 2561.3904427088. The cubic root of 6560721 is about 187.2048904322.

The spelling of 6560721 in words is "six million, five hundred sixty thousand, seven hundred twenty-one".