66306816 has 144 divisors (see below), whose sum is σ = 200884320. Its totient is φ = 21565440.

The previous prime is 66306811. The next prime is 66306841. The reversal of 66306816 is 61860366.

66306816 is a `hidden beast` number, since 6 + 630 + 6 + 8 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (66306811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366246 + ... + 366426.

It is an arithmetic number, because the mean of its divisors is an integer number (1395030).

Almost surely, 2^66306816 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 66306816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100442160).

66306816 is an abundant number, since it is smaller than the sum of its proper divisors (134577504).

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

66306816 is a wasteful number, since it uses less digits than its factorization.

66306816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 66306816 is about 8142.8997292119. The cubic root of 66306816 is about 404.7492549407.

The spelling of 66306816 in words is "sixty-six million, three hundred six thousand, eight hundred sixteen".