66542945264640 has 2112 divisors, whose sum is σ = 279328948254720. Its totient is φ = 14915374940160.

The previous prime is 66542945264639. The next prime is 66542945264693. The reversal of 66542945264640 is 4646254924566.

66542945264640 is a `hidden beast` number, since 6 + 6 + 5 + 4 + 29 + 4 + 526 + 46 + 40 = 666.

It is an unprimeable number.

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 191 ways as a sum of consecutive naturals, for example, 16100396014 + ... + 16100400146.

Almost surely, 2^{66542945264640} is an apocalyptic number.

66542945264640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66542945264640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139664474127360).

66542945264640 is an abundant number, since it is smaller than the sum of its proper divisors (212786002990080).

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

66542945264640 is a wasteful number, since it uses less digits than its factorization.

66542945264640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4245 (or 4204 counting only the distinct ones).

The product of its (nonzero) digits is 298598400, while the sum is 63.

The spelling of 66542945264640 in words is "sixty-six trillion, five hundred forty-two billion, nine hundred forty-five million, two hundred sixty-four thousand, six hundred forty".