66566556 has 96 divisors (see below), whose sum is σ = 198696960. Its totient is φ = 18878400.

The previous prime is 66566527. The next prime is 66566561. The reversal of 66566556 is 65566566.

It is a super-2 number, since 2×66566556² = 8862212755402272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 144166 + ... + 144626.

It is an arithmetic number, because the mean of its divisors is an integer number (2069760).

Almost surely, 2^66566556 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 66566556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99348480).

66566556 is an abundant number, since it is smaller than the sum of its proper divisors (132130404).

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

66566556 is a wasteful number, since it uses less digits than its factorization.

66566556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 672 (or 664 counting only the distinct ones).

The product of its digits is 972000, while the sum is 45.

The square root of 66566556 is about 8158.8330047869. The cubic root of 66566556 is about 405.2770669267.

The spelling of 66566556 in words is "sixty-six million, five hundred sixty-six thousand, five hundred fifty-six".