66128345656 has 32 divisors (see below), whose sum is σ = 124718237280. Its totient is φ = 32870275200.

The previous prime is 66128345641. The next prime is 66128345669. The reversal of 66128345656 is 65654382166.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

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, 5657290 + ... + 5668966.

It is an arithmetic number, because the mean of its divisors is an integer number (3897444915).

Almost surely, 2^66128345656 is an apocalyptic number.

It is an amenable number.

66128345656 is a deficient number, since it is larger than the sum of its proper divisors (58589891624).

66128345656 is a wasteful number, since it uses less digits than its factorization.

66128345656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15775 (or 15771 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 52.

The spelling of 66128345656 in words is "sixty-six billion, one hundred twenty-eight million, three hundred forty-five thousand, six hundred fifty-six".