66533680 has 40 divisors (see below), whose sum is σ = 157012272. Its totient is φ = 26214144.

The previous prime is 66533671. The next prime is 66533681. The reversal of 66533680 is 8633566.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (66533681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 847 + ... + 11566.

Almost surely, 2^66533680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66533680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78506136).

66533680 is an abundant number, since it is smaller than the sum of its proper divisors (90478592).

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

66533680 is a wasteful number, since it uses less digits than its factorization.

66533680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12493 (or 12487 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 66533680 is about 8156.8180070417. The cubic root of 66533680 is about 405.2103363053.

The spelling of 66533680 in words is "sixty-six million, five hundred thirty-three thousand, six hundred eighty".