66244640578 has 4 divisors (see below), whose sum is σ = 99366960870. Its totient is φ = 33122320288.

The previous prime is 66244640533. The next prime is 66244640599. The reversal of 66244640578 is 87504644266.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 61129101049 + 5115539529 = 247243^2 + 71523^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16561160143 + ... + 16561160146.

Almost surely, 2^66244640578 is an apocalyptic number.

66244640578 is a deficient number, since it is larger than the sum of its proper divisors (33122320292).

66244640578 is a wasteful number, since it uses less digits than its factorization.

66244640578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33122320291.

The product of its (nonzero) digits is 7741440, while the sum is 52.

The spelling of 66244640578 in words is "sixty-six billion, two hundred forty-four million, six hundred forty thousand, five hundred seventy-eight".