66661384 has 8 divisors (see below), whose sum is σ = 124990110. Its totient is φ = 33330688.

The previous prime is 66661379. The next prime is 66661391. The reversal of 66661384 is 48316666.

It can be written as a sum of positive squares in only one way, i.e., 50836900 + 15824484 = 7130^2 + 3978^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4166329 + ... + 4166344.

Almost surely, 2^66661384 is an apocalyptic number.

It is an amenable number.

66661384 is a deficient number, since it is larger than the sum of its proper divisors (58328726).

66661384 is a wasteful number, since it uses less digits than its factorization.

66661384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8332679 (or 8332675 counting only the distinct ones).

The product of its digits is 124416, while the sum is 40.

The square root of 66661384 is about 8164.6423069232. The cubic root of 66661384 is about 405.4694226734.

The spelling of 66661384 in words is "sixty-six million, six hundred sixty-one thousand, three hundred eighty-four".