66101980 has 72 divisors (see below), whose sum is σ = 165932928. Its totient is φ = 22038912.

The previous prime is 66101957. The next prime is 66101989. The reversal of 66101980 is 8910166.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66101989) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35349 + ... + 37171.

It is an arithmetic number, because the mean of its divisors is an integer number (2304624).

Almost surely, 2^66101980 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 66101980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82966464).

66101980 is an abundant number, since it is smaller than the sum of its proper divisors (99830948).

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

66101980 is a wasteful number, since it uses less digits than its factorization.

66101980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1883 (or 1874 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 66101980 is about 8130.3124171215. The cubic root of 66101980 is about 404.3320392207.

It can be divided in two parts, 66101 and 980, that added together give a square (67081 = 259²).

The spelling of 66101980 in words is "sixty-six million, one hundred one thousand, nine hundred eighty".