66710517678 has 40 divisors (see below), whose sum is σ = 170835402672. Its totient is φ = 19060147584.

The previous prime is 66710517661. The next prime is 66710517697. The reversal of 66710517678 is 87671501766.

66710517678 is a `hidden beast` number, since 6 + 67 + 1 + 0 + 517 + 67 + 8 = 666.

It is a super-3 number, since 3×66710517678³ (a number of 33 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 29412675 + ... + 29414942.

Almost surely, 2^66710517678 is an apocalyptic number.

66710517678 is an abundant number, since it is smaller than the sum of its proper divisors (104124884994).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66710517678 is a wasteful number, since it uses less digits than its factorization.

66710517678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58827638 (or 58827629 counting only the distinct ones).

The product of its (nonzero) digits is 2963520, while the sum is 54.

The spelling of 66710517678 in words is "sixty-six billion, seven hundred ten million, five hundred seventeen thousand, six hundred seventy-eight".