66821838172 has 24 divisors (see below), whose sum is σ = 117149457600. Its totient is φ = 33350606016.

The previous prime is 66821838151. The next prime is 66821838217. The reversal of 66821838172 is 27183812866.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13609654 + ... + 13614562.

It is an arithmetic number, because the mean of its divisors is an integer number (4881227400).

Almost surely, 2^66821838172 is an apocalyptic number.

It is an amenable number.

66821838172 is a deficient number, since it is larger than the sum of its proper divisors (50327619428).

66821838172 is a wasteful number, since it uses less digits than its factorization.

66821838172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10365 (or 10363 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 52.

The spelling of 66821838172 in words is "sixty-six billion, eight hundred twenty-one million, eight hundred thirty-eight thousand, one hundred seventy-two".