66780280 has 64 divisors (see below), whose sum is σ = 173952000. Its totient is φ = 22598784.

The previous prime is 66780253. The next prime is 66780281. The reversal of 66780280 is 8208766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66780281) 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, 20611 + ... + 23629.

It is an arithmetic number, because the mean of its divisors is an integer number (2718000).

Almost surely, 2^66780280 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 66780280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86976000).

66780280 is an abundant number, since it is smaller than the sum of its proper divisors (107171720).

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

66780280 is a wasteful number, since it uses less digits than its factorization.

66780280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3116 (or 3112 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 66780280 is about 8171.9202149801. The cubic root of 66780280 is about 405.7103420612.

The spelling of 66780280 in words is "sixty-six million, seven hundred eighty thousand, two hundred eighty".