66805633388 has 24 divisors (see below), whose sum is σ = 131376967008. Its totient is φ = 29492787456.

The previous prime is 66805633381. The next prime is 66805633403. The reversal of 66805633388 is 88333650866.

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (66805633381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27927581 + ... + 27929972.

It is an arithmetic number, because the mean of its divisors is an integer number (5474040292).

Almost surely, 2^66805633388 is an apocalyptic number.

It is an amenable number.

66805633388 is a deficient number, since it is larger than the sum of its proper divisors (64571333620).

66805633388 is a wasteful number, since it uses less digits than its factorization.

66805633388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55857593 (or 55857591 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 56.

The spelling of 66805633388 in words is "sixty-six billion, eight hundred five million, six hundred thirty-three thousand, three hundred eighty-eight".