66628668424 has 8 divisors (see below), whose sum is σ = 124928753310. Its totient is φ = 33314334208.

The previous prime is 66628668397. The next prime is 66628668443. The reversal of 66628668424 is 42486682666.

It can be written as a sum of positive squares in only one way, i.e., 39847345924 + 26781322500 = 199618^2 + 163650^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-3 number, since 3×66628668424³ (a number of 33 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4164291769 + ... + 4164291784.

Almost surely, 2^66628668424 is an apocalyptic number.

It is an amenable number.

66628668424 is a deficient number, since it is larger than the sum of its proper divisors (58300084886).

66628668424 is a wasteful number, since it uses less digits than its factorization.

66628668424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8328583559 (or 8328583555 counting only the distinct ones).

The product of its digits is 31850496, while the sum is 58.

The spelling of 66628668424 in words is "sixty-six billion, six hundred twenty-eight million, six hundred sixty-eight thousand, four hundred twenty-four".