6557 has 4 divisors (see below), whose sum is σ = 6720. Its totient is φ = 6396.

The previous prime is 6553. The next prime is 6563. The reversal of 6557 is 7556.

6557 is nontrivially palindromic in base 6.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 6557 - 2² = 6553 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6551) 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, 38 + ... + 120.

It is an arithmetic number, because the mean of its divisors is an integer number (1680).

It is an amenable number.

6557 is a deficient number, since it is larger than the sum of its proper divisors (163).

6557 is an equidigital number, since it uses as much as digits as its factorization.

With its predecessor (6556) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (162).

6557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162.

The product of its digits is 1050, while the sum is 23.

The square root of 6557 is about 80.9753048775. The cubic root of 6557 is about 18.7169491826.

Subtracting 6557 from its reverse (7556), we obtain a palindrome (999).

The spelling of 6557 in words is "six thousand, five hundred fifty-seven".