66566566 has 16 divisors (see below), whose sum is σ = 109077840. Its totient is φ = 30215680.

The previous prime is 66566561. The next prime is 66566567.

66566566 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×66566566³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66566561) 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, 18810 + ... + 22066.

It is an arithmetic number, because the mean of its divisors is an integer number (6817365).

Almost surely, 2^66566566 is an apocalyptic number.

66566566 is a deficient number, since it is larger than the sum of its proper divisors (42511274).

66566566 is a wasteful number, since it uses less digits than its factorization.

66566566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4199.

The product of its digits is 1166400, while the sum is 46.

The square root of 66566566 is about 8158.8336176196. The cubic root of 66566566 is about 405.2770872210.

The spelling of 66566566 in words is "sixty-six million, five hundred sixty-six thousand, five hundred sixty-six".