66789669488640 has 1536 divisors, whose sum is σ = 264176640000000. Its totient is φ = 14359244046336.

The previous prime is 66789669488617. The next prime is 66789669488719. The reversal of 66789669488640 is 4688496698766.

It is a tau number, because it is divible by the number of its divisors (1536).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 29830132641 + ... + 29830134879.

It is an arithmetic number, because the mean of its divisors is an integer number (171990000000).

Almost surely, 2^{66789669488640} is an apocalyptic number.

66789669488640 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 66789669488640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132088320000000).

66789669488640 is an abundant number, since it is smaller than the sum of its proper divisors (197386970511360).

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

66789669488640 is a wasteful number, since it uses less digits than its factorization.

66789669488640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2458 (or 2424 counting only the distinct ones).

The product of its (nonzero) digits is 36118462464, while the sum is 87.

The spelling of 66789669488640 in words is "sixty-six trillion, seven hundred eighty-nine billion, six hundred sixty-nine million, four hundred eighty-eight thousand, six hundred forty".