66509760 has 112 divisors (see below), whose sum is σ = 218541600. Its totient is φ = 17117184.

The previous prime is 66509759. The next prime is 66509783. The reversal of 66509760 is 6790566.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26646 + ... + 29034.

Almost surely, 2^66509760 is an apocalyptic number.

66509760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66509760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109270800).

66509760 is an abundant number, since it is smaller than the sum of its proper divisors (152031840).

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

66509760 is a wasteful number, since it uses less digits than its factorization.

66509760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2438 (or 2428 counting only the distinct ones).

The product of its (nonzero) digits is 68040, while the sum is 39.

The square root of 66509760 is about 8155.3516171898. The cubic root of 66509760 is about 405.1617704610.

The spelling of 66509760 in words is "sixty-six million, five hundred nine thousand, seven hundred sixty".