66861126978 has 16 divisors (see below), whose sum is σ = 134684286240. Its totient is φ = 22126703616.

The previous prime is 66861126877. The next prime is 66861126979. The reversal of 66861126978 is 87962116866.

It is not an unprimeable number, because it can be changed into a prime (66861126979) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 40083775 + ... + 40085442.

It is an arithmetic number, because the mean of its divisors is an integer number (8417767890).

Almost surely, 2^66861126978 is an apocalyptic number.

66861126978 is an abundant number, since it is smaller than the sum of its proper divisors (67823159262).

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

66861126978 is a wasteful number, since it uses less digits than its factorization.

66861126978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80169361.

The product of its digits is 10450944, while the sum is 60.

The spelling of 66861126978 in words is "sixty-six billion, eight hundred sixty-one million, one hundred twenty-six thousand, nine hundred seventy-eight".