66809568 has 96 divisors (see below), whose sum is σ = 205922304. Its totient is φ = 18565632.

The previous prime is 66809551. The next prime is 66809569. The reversal of 66809568 is 86590866.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66809569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23521 + ... + 26207.

It is an arithmetic number, because the mean of its divisors is an integer number (2145024).

Almost surely, 2^66809568 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 66809568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102961152).

66809568 is an abundant number, since it is smaller than the sum of its proper divisors (139112736).

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

66809568 is a wasteful number, since it uses less digits than its factorization.

66809568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2744 (or 2736 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 48.

The square root of 66809568 is about 8173.7120086286. The cubic root of 66809568 is about 405.7696445370.

The spelling of 66809568 in words is "sixty-six million, eight hundred nine thousand, five hundred sixty-eight".