66645217584000 has 640 divisors, whose sum is σ = 270024264338400. Its totient is φ = 16156412928000.

The previous prime is 66645217583933. The next prime is 66645217584013. The reversal of 66645217584000 is 48571254666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11918556 + ... + 16593444.

Almost surely, 2^{66645217584000} is an apocalyptic number.

66645217584000 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 66645217584000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135012132169200).

66645217584000 is an abundant number, since it is smaller than the sum of its proper divisors (203379046754400).

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

66645217584000 is a wasteful number, since it uses less digits than its factorization.

66645217584000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4674941 (or 4674910 counting only the distinct ones).

The product of its (nonzero) digits is 9676800, while the sum is 54.

The spelling of 66645217584000 in words is "sixty-six trillion, six hundred forty-five billion, two hundred seventeen million, five hundred eighty-four thousand".