6511 has 4 divisors (see below), whose sum is σ = 6912. Its totient is φ = 6112.

The previous prime is 6491. The next prime is 6521. The reversal of 6511 is 1156.

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

It is a cyclic number.

It is not a de Polignac number, because 6511 - 2¹¹ = 4463 is a prime.

It is a Duffinian number.

It is a plaindrome in base 8.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 6491 and 6500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6521) 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, 175 + ... + 208.

It is an arithmetic number, because the mean of its divisors is an integer number (1728).

6511 is a deficient number, since it is larger than the sum of its proper divisors (401).

6511 is a wasteful number, since it uses less digits than its factorization.

6511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400.

The product of its digits is 30, while the sum is 13.

The square root of 6511 is about 80.6907677495. The cubic root of 6511 is about 18.6730774466.

Adding to 6511 its reverse (1156), we get a palindrome (7667).

The spelling of 6511 in words is "six thousand, five hundred eleven".