66665066624 has 64 divisors (see below), whose sum is σ = 143250833880. Its totient is φ = 30720000000.

The previous prime is 66665066617. The next prime is 66665066639. The reversal of 66665066624 is 42666056666.

It can be written as a sum of positive squares in 4 ways, for example, as 66584641600 + 80425024 = 258040^2 + 8968^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×66665066624² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1035374 + ... + 1097874.

Almost surely, 2^66665066624 is an apocalyptic number.

66665066624 is a gapful number since it is divisible by the number (64) 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 66665066624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71625416940).

66665066624 is an abundant number, since it is smaller than the sum of its proper divisors (76585767256).

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

66665066624 is a wasteful number, since it uses less digits than its factorization.

66665066624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63169 (or 63157 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 53.

The spelling of 66665066624 in words is "sixty-six billion, six hundred sixty-five million, sixty-six thousand, six hundred twenty-four".