66544560 has 120 divisors (see below), whose sum is σ = 231257520. Its totient is φ = 17127936.

The previous prime is 66544553. The next prime is 66544561. The reversal of 66544560 is 6544566.

It is a happy number.

66544560 is a `hidden beast` number, since 66 + 544 + 56 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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 (66544561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19287 + ... + 22473.

It is an arithmetic number, because the mean of its divisors is an integer number (1927146).

Almost surely, 2^66544560 is an apocalyptic number.

66544560 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 66544560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115628760).

66544560 is an abundant number, since it is smaller than the sum of its proper divisors (164712960).

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

66544560 is a wasteful number, since it uses less digits than its factorization.

66544560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3235 (or 3226 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 66544560 is about 8157.4849065138. The cubic root of 66544560 is about 405.2324226039.

The spelling of 66544560 in words is "sixty-six million, five hundred forty-four thousand, five hundred sixty".