66864816 has 60 divisors (see below), whose sum is σ = 189097272. Its totient is φ = 22053888.

The previous prime is 66864797. The next prime is 66864817. The reversal of 66864816 is 61846866.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (66864817) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11575 + ... + 16361.

Almost surely, 2^66864816 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 66864816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94548636).

66864816 is an abundant number, since it is smaller than the sum of its proper divisors (122232456).

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

66864816 is a wasteful number, since it uses less digits than its factorization.

66864816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4898 (or 4889 counting only the distinct ones).

The product of its digits is 331776, while the sum is 45.

The square root of 66864816 is about 8177.0909252619. The cubic root of 66864816 is about 405.8814637736.

The spelling of 66864816 in words is "sixty-six million, eight hundred sixty-four thousand, eight hundred sixteen".