66678780694 has 32 divisors (see below), whose sum is σ = 102555611136. Its totient is φ = 32505543840.

The previous prime is 66678780691. The next prime is 66678780703. The reversal of 66678780694 is 49608787666.

It is a Harshad number since it is a multiple of its sum of digits (67).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66678780691) 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, 5255979 + ... + 5268649.

It is an arithmetic number, because the mean of its divisors is an integer number (3204862848).

Almost surely, 2^66678780694 is an apocalyptic number.

66678780694 is a deficient number, since it is larger than the sum of its proper divisors (35876830442).

66678780694 is a wasteful number, since it uses less digits than its factorization.

66678780694 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13140.

The product of its (nonzero) digits is 146313216, while the sum is 67.

The spelling of 66678780694 in words is "sixty-six billion, six hundred seventy-eight million, seven hundred eighty thousand, six hundred ninety-four".