66561968 has 20 divisors (see below), whose sum is σ = 140688168. Its totient is φ = 30255360.

The previous prime is 66561967. The next prime is 66561973. The reversal of 66561968 is 86916566.

It is not an unprimeable number, because it can be changed into a prime (66561961) 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 3 ways as a sum of consecutive naturals, for example, 188921 + ... + 189272.

Almost surely, 2^66561968 is an apocalyptic number.

It is an amenable number.

66561968 is an abundant number, since it is smaller than the sum of its proper divisors (74126200).

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

66561968 is a wasteful number, since it uses less digits than its factorization.

66561968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378212 (or 378206 counting only the distinct ones).

The product of its digits is 466560, while the sum is 47.

The square root of 66561968 is about 8158.5518322800. The cubic root of 66561968 is about 405.2677556748.

The spelling of 66561968 in words is "sixty-six million, five hundred sixty-one thousand, nine hundred sixty-eight".