66778156653 has 16 divisors (see below), whose sum is σ = 99193019520. Its totient is φ = 39677206464.

The previous prime is 66778156649. The next prime is 66778156681. The reversal of 66778156653 is 35665187766.

It is not a de Polignac number, because 66778156653 - 2² = 66778156649 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66778156633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29520601 + ... + 29522862.

It is an arithmetic number, because the mean of its divisors is an integer number (6199563720).

Almost surely, 2^66778156653 is an apocalyptic number.

It is an amenable number.

66778156653 is a deficient number, since it is larger than the sum of its proper divisors (32414862867).

66778156653 is a wasteful number, since it uses less digits than its factorization.

66778156653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59043508.

The product of its digits is 38102400, while the sum is 60.

The spelling of 66778156653 in words is "sixty-six billion, seven hundred seventy-eight million, one hundred fifty-six thousand, six hundred fifty-three".