66646640793600 has 1728 divisors, whose sum is σ = 282317555520000. Its totient is φ = 15016432435200.

The previous prime is 66646640793581. The next prime is 66646640793611. The reversal of 66646640793600 is 639704664666.

It is a super-2 number, since 2×66646640793600² (a number of 28 digits) contains 22 as substring.

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

It is a congruent number.

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 143 ways as a sum of consecutive naturals, for example, 11221859431 + ... + 11221865369.

It is an arithmetic number, because the mean of its divisors is an integer number (163378215000).

Almost surely, 2^{66646640793600} is an apocalyptic number.

66646640793600 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 66646640793600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141158777760000).

66646640793600 is an abundant number, since it is smaller than the sum of its proper divisors (215670914726400).

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

66646640793600 is a wasteful number, since it uses less digits than its factorization.

66646640793600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6069 (or 6027 counting only the distinct ones).

The product of its (nonzero) digits is 141087744, while the sum is 63.

The spelling of 66646640793600 in words is "sixty-six trillion, six hundred forty-six billion, six hundred forty million, seven hundred ninety-three thousand, six hundred".