66018754521 has 24 divisors (see below), whose sum is σ = 95731379744. Its totient is φ = 43841476800.

The previous prime is 66018754517. The next prime is 66018754537. The reversal of 66018754521 is 12545781066.

66018754521 is a `hidden beast` number, since 6 + 6 + 0 + 1 + 87 + 545 + 21 = 666.

It is not a de Polignac number, because 66018754521 - 2² = 66018754517 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66018754541) by changing a digit.

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 in 23 ways as a sum of consecutive naturals, for example, 4969530 + ... + 4982796.

Almost surely, 2^66018754521 is an apocalyptic number.

It is an amenable number.

66018754521 is a deficient number, since it is larger than the sum of its proper divisors (29712625223).

66018754521 is a wasteful number, since it uses less digits than its factorization.

66018754521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15381 (or 15378 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 66018754521 in words is "sixty-six billion, eighteen million, seven hundred fifty-four thousand, five hundred twenty-one".