6642 has 20 divisors (see below), whose sum is σ = 15246. Its totient is φ = 2160.

The previous prime is 6637. The next prime is 6653. The reversal of 6642 is 2466.

6642 is a `hidden beast` number, since 664 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6561 + 81 = 81^2 + 9^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 10.

It is an unprimeable number.

6642 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 142 + ... + 182.

2⁶⁶⁴² is an apocalyptic number.

It is a pronic number, being equal to 81×82.

It is a practical number, because each smaller number is the sum of distinct divisors of 6642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7623).

6642 is an abundant number, since it is smaller than the sum of its proper divisors (8604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6642 is a wasteful number, since it uses less digits than its factorization.

6642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55 (or 46 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 6642 is about 81.4984662432. The cubic root of 6642 is about 18.7974796682.

It can be divided in two parts, 664 and 2, that added together give a palindrome (666).

The spelling of 6642 in words is "six thousand, six hundred forty-two".