66609768960 has 960 divisors, whose sum is σ = 280116714240. Its totient is φ = 14956462080.

The previous prime is 66609768949. The next prime is 66609768961. The reversal of 66609768960 is 6986790666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a super-2 number, since 2×66609768960² (a number of 22 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 not an unprimeable number, because it can be changed into a prime (66609768961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 240468342 + ... + 240468618.

It is an arithmetic number, because the mean of its divisors is an integer number (291788244).

Almost surely, 2^66609768960 is an apocalyptic number.

66609768960 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 66609768960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140058357120).

66609768960 is an abundant number, since it is smaller than the sum of its proper divisors (213506945280).

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

66609768960 is a wasteful number, since it uses less digits than its factorization.

66609768960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 35271936, while the sum is 63.

The spelling of 66609768960 in words is "sixty-six billion, six hundred nine million, seven hundred sixty-eight thousand, nine hundred sixty".