66172180 has 12 divisors (see below), whose sum is σ = 138961620. Its totient is φ = 26468864.

The previous prime is 66172163. The next prime is 66172181. The reversal of 66172180 is 8127166.

It can be written as a sum of positive squares in 2 ways, for example, as 30316036 + 35856144 = 5506^2 + 5988^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66172181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1654285 + ... + 1654324.

It is an arithmetic number, because the mean of its divisors is an integer number (11580135).

Almost surely, 2^66172180 is an apocalyptic number.

It is an amenable number.

66172180 is an abundant number, since it is smaller than the sum of its proper divisors (72789440).

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

66172180 is a wasteful number, since it uses less digits than its factorization.

66172180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3308618 (or 3308616 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 66172180 is about 8134.6284487984. The cubic root of 66172180 is about 404.4751215063.

The spelling of 66172180 in words is "sixty-six million, one hundred seventy-two thousand, one hundred eighty".