66509980 has 24 divisors (see below), whose sum is σ = 140238000. Its totient is φ = 26496000.

The previous prime is 66509969. The next prime is 66510007. The reversal of 66509980 is 8990566.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1605 + ... + 11644.

It is an arithmetic number, because the mean of its divisors is an integer number (5843250).

Almost surely, 2^66509980 is an apocalyptic number.

It is an amenable number.

66509980 is an abundant number, since it is smaller than the sum of its proper divisors (73728020).

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

66509980 is a wasteful number, since it uses less digits than its factorization.

66509980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13509 (or 13507 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

The square root of 66509980 is about 8155.3651052543. The cubic root of 66509980 is about 405.1622171899.

The spelling of 66509980 in words is "sixty-six million, five hundred nine thousand, nine hundred eighty".