66643560 has 160 divisors (see below), whose sum is σ = 228080160. Its totient is φ = 17449344.

The previous prime is 66643541. The next prime is 66643561. The reversal of 66643560 is 6534666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (66643561) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 216927 + ... + 217233.

It is an arithmetic number, because the mean of its divisors is an integer number (1425501).

Almost surely, 2^66643560 is an apocalyptic number.

66643560 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 66643560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114040080).

66643560 is an abundant number, since it is smaller than the sum of its proper divisors (161436600).

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

66643560 is a wasteful number, since it uses less digits than its factorization.

66643560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The square root of 66643560 is about 8163.5506980725. The cubic root of 66643560 is about 405.4332811535.

The spelling of 66643560 in words is "sixty-six million, six hundred forty-three thousand, five hundred sixty".