66556520545 has 16 divisors (see below), whose sum is σ = 80316126720. Its totient is φ = 52947126400.

The previous prime is 66556520543. The next prime is 66556520581. The reversal of 66556520545 is 54502565566.

It is not a de Polignac number, because 66556520545 - 2¹ = 66556520543 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66556520543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 641616 + ... + 738094.

It is an arithmetic number, because the mean of its divisors is an integer number (5019757920).

Almost surely, 2^66556520545 is an apocalyptic number.

It is an amenable number.

66556520545 is a deficient number, since it is larger than the sum of its proper divisors (13759606175).

66556520545 is a wasteful number, since it uses less digits than its factorization.

66556520545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97256.

The product of its (nonzero) digits is 5400000, while the sum is 49.

The spelling of 66556520545 in words is "sixty-six billion, five hundred fifty-six million, five hundred twenty thousand, five hundred forty-five".