66556 has 12 divisors (see below), whose sum is σ = 133168. Its totient is φ = 28512.

The previous prime is 66553. The next prime is 66569. The reversal of 66556 is 65566.

66556 = T₁₈ + T₁₉ + ... + T₇₃.

66556 is an admirable number.

It is a super-2 number, since 2×66556² = 8859402272, which contains 22 as substring.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 2377 = 66556 / (6 + 6 + 5 + 5 + 6).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66553) 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, 1161 + ... + 1216.

2⁶⁶⁵⁵⁶ is an apocalyptic number.

It is an amenable number.

66556 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66584).

66556 is a wasteful number, since it uses less digits than its factorization.

66556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2388 (or 2386 counting only the distinct ones).

The product of its digits is 5400, while the sum is 28.

The square root of 66556 is about 257.9844956582. The cubic root of 66556 is about 40.5255643101.

Subtracting from 66556 its reverse (65566), we obtain a triangular number (990 = T₄₄).

The spelling of 66556 in words is "sixty-six thousand, five hundred fifty-six".