6561565 has 16 divisors (see below), whose sum is σ = 8100288. Its totient is φ = 5101056.

The previous prime is 6561557. The next prime is 6561589. The reversal of 6561565 is 5651656.

It is a cyclic number.

It is not a de Polignac number, because 6561565 - 2³ = 6561557 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 6561565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40174 + ... + 40336.

It is an arithmetic number, because the mean of its divisors is an integer number (506268).

Almost surely, 2^6561565 is an apocalyptic number.

It is an amenable number.

6561565 is a deficient number, since it is larger than the sum of its proper divisors (1538723).

6561565 is a wasteful number, since it uses less digits than its factorization.

6561565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348.

The product of its digits is 27000, while the sum is 34.

The square root of 6561565 is about 2561.5551916756. Note that the first 3 decimals coincide. The cubic root of 6561565 is about 187.2129177081.

Subtracting from 6561565 its reverse (5651656), we obtain a palindrome (909909).

The spelling of 6561565 in words is "six million, five hundred sixty-one thousand, five hundred sixty-five".