66168640 has 56 divisors (see below), whose sum is σ = 165872160. Its totient is φ = 25072128.

The previous prime is 66168623. The next prime is 66168649. The reversal of 66168640 is 4686166.

66168640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 66168640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66168649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 639 + ... + 11521.

Almost surely, 2^66168640 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 66168640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82936080).

66168640 is an abundant number, since it is smaller than the sum of its proper divisors (99703520).

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

66168640 is a wasteful number, since it uses less digits than its factorization.

66168640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10919 (or 10909 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 66168640 is about 8134.4108575852. The cubic root of 66168640 is about 404.4679086692.

The spelling of 66168640 in words is "sixty-six million, one hundred sixty-eight thousand, six hundred forty".