66131856 has 160 divisors (see below), whose sum is σ = 228556800. Its totient is φ = 17884800.

The previous prime is 66131843. The next prime is 66131873. The reversal of 66131856 is 65813166.

It is a happy number.

66131856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 66131856.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 56881 + ... + 58031.

It is an arithmetic number, because the mean of its divisors is an integer number (1428480).

Almost surely, 2^66131856 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 66131856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114278400).

66131856 is an abundant number, since it is smaller than the sum of its proper divisors (162424944).

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

66131856 is a wasteful number, since it uses less digits than its factorization.

66131856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1194 (or 1182 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66131856 is about 8132.1495313355. The cubic root of 66131856 is about 404.3929451349.

The spelling of 66131856 in words is "sixty-six million, one hundred thirty-one thousand, eight hundred fifty-six".