66561288 has 16 divisors (see below), whose sum is σ = 166403280. Its totient is φ = 22187088.

The previous prime is 66561283. The next prime is 66561289. The reversal of 66561288 is 88216566.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (66561281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1386670 + ... + 1386717.

It is an arithmetic number, because the mean of its divisors is an integer number (10400205).

Almost surely, 2^66561288 is an apocalyptic number.

It is an amenable number.

66561288 is an abundant number, since it is smaller than the sum of its proper divisors (99841992).

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

66561288 is a wasteful number, since it uses less digits than its factorization.

66561288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2773396 (or 2773392 counting only the distinct ones).

The product of its digits is 138240, while the sum is 42.

The square root of 66561288 is about 8158.5101581110. The cubic root of 66561288 is about 405.2663755924.

The spelling of 66561288 in words is "sixty-six million, five hundred sixty-one thousand, two hundred eighty-eight".