66945600 has 126 divisors (see below), whose sum is σ = 237991650. Its totient is φ = 17848320.

The previous prime is 66945587. The next prime is 66945649. The reversal of 66945600 is 654966.

It is a happy number.

66945600 is a `hidden beast` number, since 6 + 6 + 9 + 45 + 600 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 19501056 + 47444544 = 4416^2 + 6888^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 12076 + ... + 16724.

Almost surely, 2^66945600 is an apocalyptic number.

66945600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66945600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118995825).

66945600 is an abundant number, since it is smaller than the sum of its proper divisors (171046050).

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

66945600 is a wasteful number, since it uses less digits than its factorization.

66945600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4677 (or 4659 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 66945600 is about 8182.0290881908. The cubic root of 66945600 is about 406.0448557945.

The spelling of 66945600 in words is "sixty-six million, nine hundred forty-five thousand, six hundred".