66565680720 has 1280 divisors, whose sum is σ = 285410304000. Its totient is φ = 12680478720.

The previous prime is 66565680719. The next prime is 66565680721. The reversal of 66565680720 is 2708656566.

It is an interprime number because it is at equal distance from previous prime (66565680719) and next prime (66565680721).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66565680721) by changing a digit.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 911858604 + ... + 911858676.

It is an arithmetic number, because the mean of its divisors is an integer number (222976800).

Almost surely, 2^66565680720 is an apocalyptic number.

66565680720 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 66565680720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142705152000).

66565680720 is an abundant number, since it is smaller than the sum of its proper divisors (218844623280).

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

66565680720 is a wasteful number, since it uses less digits than its factorization.

66565680720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 3628800, while the sum is 51.

The spelling of 66565680720 in words is "sixty-six billion, five hundred sixty-five million, six hundred eighty thousand, seven hundred twenty".