66855888 has 120 divisors (see below), whose sum is σ = 211097600. Its totient is φ = 20243520.

The previous prime is 66855881. The next prime is 66855907. The reversal of 66855888 is 88855866.

66855888 is a `hidden beast` number, since 6 + 6 + 8 + 558 + 88 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66855881) 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, 51633 + ... + 52911.

Almost surely, 2^66855888 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 66855888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105548800).

66855888 is an abundant number, since it is smaller than the sum of its proper divisors (144241712).

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

66855888 is a wasteful number, since it uses less digits than its factorization.

66855888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1318 (or 1295 counting only the distinct ones).

The product of its digits is 3686400, while the sum is 54.

The square root of 66855888 is about 8176.5449916208. The cubic root of 66855888 is about 405.8633981140.

The spelling of 66855888 in words is "sixty-six million, eight hundred fifty-five thousand, eight hundred eighty-eight".