66799616 has 72 divisors (see below), whose sum is σ = 145380690. Its totient is φ = 30670848.

The previous prime is 66799609. The next prime is 66799703. The reversal of 66799616 is 61699766.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 24601600 + 42198016 = 4960^2 + 6496^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 346016 + ... + 346208.

Almost surely, 2^66799616 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 66799616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72690345).

66799616 is an abundant number, since it is smaller than the sum of its proper divisors (78581074).

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

66799616 is a wasteful number, since it uses less digits than its factorization.

66799616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241 (or 208 counting only the distinct ones).

The product of its digits is 734832, while the sum is 50.

The square root of 66799616 is about 8173.1032050256. The cubic root of 66799616 is about 405.7494956265.

The spelling of 66799616 in words is "sixty-six million, seven hundred ninety-nine thousand, six hundred sixteen".