66909760 has 56 divisors (see below), whose sum is σ = 166274496. Its totient is φ = 25597440.

The previous prime is 66909709. The next prime is 66909767. The reversal of 66909760 is 6790966.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (66909767) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2815 + ... + 11905.

Almost surely, 2^66909760 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 66909760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83137248).

66909760 is an abundant number, since it is smaller than the sum of its proper divisors (99364736).

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

66909760 is a wasteful number, since it uses less digits than its factorization.

66909760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9131 (or 9121 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 43.

The square root of 66909760 is about 8179.8386292151. The cubic root of 66909760 is about 405.9723827947.

The spelling of 66909760 in words is "sixty-six million, nine hundred nine thousand, seven hundred sixty".