66381861684 has 12 divisors (see below), whose sum is σ = 154891010624. Its totient is φ = 22127287224.

The previous prime is 66381861671. The next prime is 66381861691. The reversal of 66381861684 is 48616818366.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2765910892 + ... + 2765910915.

Almost surely, 2^66381861684 is an apocalyptic number.

It is an amenable number.

66381861684 is an abundant number, since it is smaller than the sum of its proper divisors (88509148940).

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

66381861684 is a wasteful number, since it uses less digits than its factorization.

66381861684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5531821814 (or 5531821812 counting only the distinct ones).

The product of its digits is 7962624, while the sum is 57.

The spelling of 66381861684 in words is "sixty-six billion, three hundred eighty-one million, eight hundred sixty-one thousand, six hundred eighty-four".