66750728 has 32 divisors (see below), whose sum is σ = 137808000. Its totient is φ = 30058560.

The previous prime is 66750713. The next prime is 66750737. The reversal of 66750728 is 82705766.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6113 + ... + 13071.

It is an arithmetic number, because the mean of its divisors is an integer number (4306500).

Almost surely, 2^66750728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66750728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68904000).

66750728 is an abundant number, since it is smaller than the sum of its proper divisors (71057272).

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

66750728 is a wasteful number, since it uses less digits than its factorization.

66750728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7085 (or 7081 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 41.

The square root of 66750728 is about 8170.1118719391. Note that the first 3 decimals coincide. The cubic root of 66750728 is about 405.6504874603.

The spelling of 66750728 in words is "sixty-six million, seven hundred fifty thousand, seven hundred twenty-eight".