66366036656640 has 1440 divisors, whose sum is σ = 278222399769600. Its totient is φ = 14565884755968.

The previous prime is 66366036656617. The next prime is 66366036656671. The reversal of 66366036656640 is 4665663066366.

66366036656640 is a `hidden beast` number, since 6 + 6 + 3 + 6 + 6 + 0 + 3 + 66 + 566 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2812227561 + ... + 2812251159.

It is an arithmetic number, because the mean of its divisors is an integer number (193209999840).

Almost surely, 2^{66366036656640} is an apocalyptic number.

66366036656640 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 66366036656640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139111199884800).

66366036656640 is an abundant number, since it is smaller than the sum of its proper divisors (211856363112960).

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

66366036656640 is a wasteful number, since it uses less digits than its factorization.

66366036656640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23742 (or 23716 counting only the distinct ones).

The product of its (nonzero) digits is 302330880, while the sum is 63.

The spelling of 66366036656640 in words is "sixty-six trillion, three hundred sixty-six billion, thirty-six million, six hundred fifty-six thousand, six hundred forty".