66728 has 16 divisors (see below), whose sum is σ = 132000. Its totient is φ = 31536.

The previous prime is 66721. The next prime is 66733. The reversal of 66728 is 82766.

66728 = 2² + 3² + ... + 58².

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 66728.

It is not an unprimeable number, because it can be changed into a prime (66721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68 + ... + 371.

It is an arithmetic number, because the mean of its divisors is an integer number (8250).

2⁶⁶⁷²⁸ is an apocalyptic number.

It is an amenable number.

66728 is a deficient number, since it is larger than the sum of its proper divisors (65272).

66728 is a wasteful number, since it uses less digits than its factorization.

66728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 460 counting only the distinct ones).

The product of its digits is 4032, while the sum is 29.

The square root of 66728 is about 258.3176339316. The cubic root of 66728 is about 40.5604442165.

The spelling of 66728 in words is "sixty-six thousand, seven hundred twenty-eight".