66745563978 has 16 divisors (see below), whose sum is σ = 133629186240. Its totient is φ = 22225511616.

The previous prime is 66745563977. The next prime is 66745564007. The reversal of 66745563978 is 87936554766.

It is not an unprimeable number, because it can be changed into a prime (66745563971) 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, 5746143 + ... + 5757746.

It is an arithmetic number, because the mean of its divisors is an integer number (8351824140).

Almost surely, 2^66745563978 is an apocalyptic number.

66745563978 is an abundant number, since it is smaller than the sum of its proper divisors (66883622262).

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

66745563978 is a wasteful number, since it uses less digits than its factorization.

66745563978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11504861.

The product of its digits is 228614400, while the sum is 66.

The spelling of 66745563978 in words is "sixty-six billion, seven hundred forty-five million, five hundred sixty-three thousand, nine hundred seventy-eight".