6651 has 6 divisors (see below), whose sum is σ = 9620.
Its totient is φ = 4428.
The previous prime is 6637. The next prime is 6653. The reversal of 6651 is 1566.
6651 is a `hidden beast` number, since 665 + 1 = 666.
It is not a de Polignac number, because 6651 - 25 = 6619 is a prime.
It is a Duffinian number.
It is a nialpdrome in base 10.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 6651.
It is not an unprimeable number, because it can be changed into a prime (6653) by changing a digit.
It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 361 + ... + 378.
6651 is a deficient number, since it is larger than the sum of its proper divisors (2969).
6651 is a wasteful number, since it uses less digits than its factorization.
6651 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 745 (or 742 counting only the distinct ones).
The product of its digits is 180, while the sum is 18.
The square root of 6651 is about 81.5536633144.
The cubic root of 6651 is about 18.8059661161.
It can be divided in two parts, 665 and 1, that added together give a palindrome (666).
The spelling of 6651 in words is "six thousand, six hundred fifty-one".