66128720804 has 12 divisors (see below), whose sum is σ = 118416546864. Its totient is φ = 32295421704.

The previous prime is 66128720797. The next prime is 66128720807. The reversal of 66128720804 is 40802782166.

66128720804 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (66128720807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192234482 + ... + 192234825.

It is an arithmetic number, because the mean of its divisors is an integer number (9868045572).

Almost surely, 2^66128720804 is an apocalyptic number.

It is an amenable number.

66128720804 is a deficient number, since it is larger than the sum of its proper divisors (52287826060).

66128720804 is a wasteful number, since it uses less digits than its factorization.

66128720804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384469354 (or 384469352 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 44.

The spelling of 66128720804 in words is "sixty-six billion, one hundred twenty-eight million, seven hundred twenty thousand, eight hundred four".