660728 has 8 divisors (see below), whose sum is σ = 1238880. Its totient is φ = 330360.

The previous prime is 660727. The next prime is 660731. The reversal of 660728 is 827066.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×660728² = 873122979968, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 660728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41288 + ... + 41303.

It is an arithmetic number, because the mean of its divisors is an integer number (154860).

2⁶⁶⁰⁷²⁸ is an apocalyptic number.

It is an amenable number.

660728 is a deficient number, since it is larger than the sum of its proper divisors (578152).

660728 is a wasteful number, since it uses less digits than its factorization.

660728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82597 (or 82593 counting only the distinct ones).

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

The square root of 660728 is about 812.8517700048. The cubic root of 660728 is about 87.0978772490.

The spelling of 660728 in words is "six hundred sixty thousand, seven hundred twenty-eight".