66782214728 has 8 divisors (see below), whose sum is σ = 125216652630. Its totient is φ = 33391107360.

The previous prime is 66782214727. The next prime is 66782214749. The reversal of 66782214728 is 82741228766.

66782214728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 63898739524 + 2883475204 = 252782^2 + 53698^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×66782214728² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66782214728.

It is not an unprimeable number, because it can be changed into a prime (66782214727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4173888413 + ... + 4173888428.

Almost surely, 2^66782214728 is an apocalyptic number.

It is an amenable number.

66782214728 is a deficient number, since it is larger than the sum of its proper divisors (58434437902).

66782214728 is a wasteful number, since it uses less digits than its factorization.

66782214728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8347776847 (or 8347776843 counting only the distinct ones).

The product of its digits is 3612672, while the sum is 53.

The spelling of 66782214728 in words is "sixty-six billion, seven hundred eighty-two million, two hundred fourteen thousand, seven hundred twenty-eight".