6638 has 4 divisors (see below), whose sum is σ = 9960. Its totient is φ = 3318.

The previous prime is 6637. The next prime is 6653. The reversal of 6638 is 8366.

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

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1658 + ... + 1661.

It is an arithmetic number, because the mean of its divisors is an integer number (2490).

2⁶⁶³⁸ is an apocalyptic number.

6638 is a deficient number, since it is larger than the sum of its proper divisors (3322).

6638 is a wasteful number, since it uses less digits than its factorization.

6638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3321.

The product of its digits is 864, while the sum is 23.

The square root of 6638 is about 81.4739222083. The cubic root of 6638 is about 18.7937054527.

Subtracting 6638 from its reverse (8366), we obtain a cube (1728 = 12³).

It can be divided in two parts, 6 and 638, that multiplied together give a triangular number (3828 = T₈₇).

The spelling of 6638 in words is "six thousand, six hundred thirty-eight".