66955728 has 80 divisors (see below), whose sum is σ = 199737216. Its totient is φ = 18931200.

The previous prime is 66955727. The next prime is 66955729. The reversal of 66955728 is 82755966.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66955727) and next prime (66955729).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66955723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32950 + ... + 34922.

Almost surely, 2^66955728 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 66955728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99868608).

66955728 is an abundant number, since it is smaller than the sum of its proper divisors (132781488).

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

66955728 is a wasteful number, since it uses less digits than its factorization.

66955728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2092 (or 2086 counting only the distinct ones).

The product of its digits is 907200, while the sum is 48.

The square root of 66955728 is about 8182.6479821632. The cubic root of 66955728 is about 406.0653312001.

The spelling of 66955728 in words is "sixty-six million, nine hundred fifty-five thousand, seven hundred twenty-eight".