6505 has 4 divisors (see below), whose sum is σ = 7812. Its totient is φ = 5200.

The previous prime is 6491. The next prime is 6521. The reversal of 6505 is 5056.

It is a happy number.

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 729 + 5776 = 27^2 + 76^2 .

It is not a de Polignac number, because 6505 - 2⁵ = 6473 is a prime.

It is a fibodiv number, since the Fibonacci-like sequence with seeds 65 and 5 contains 6505 itself.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

6505 is a lucky number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 646 + ... + 655.

It is an arithmetic number, because the mean of its divisors is an integer number (1953).

2⁶⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

6505 is a deficient number, since it is larger than the sum of its proper divisors (1307).

6505 is a wasteful number, since it uses less digits than its factorization.

6505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1306.

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 6505 is about 80.6535802057. The cubic root of 6505 is about 18.6673398283.

The spelling of 6505 in words is "six thousand, five hundred five".