66554550 has 72 divisors (see below), whose sum is σ = 180334440. Its totient is φ = 17596800.

The previous prime is 66554503. The next prime is 66554557. The reversal of 66554550 is 5545566.

It is a happy number.

66554550 is a `hidden beast` number, since 6 + 65 + 545 + 50 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66554557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 58386 + ... + 59514.

It is an arithmetic number, because the mean of its divisors is an integer number (2504645).

Almost surely, 2^66554550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66554550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90167220).

66554550 is an abundant number, since it is smaller than the sum of its proper divisors (113779890).

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

66554550 is a wasteful number, since it uses less digits than its factorization.

66554550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1278 (or 1270 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 36.

The square root of 66554550 is about 8158.0972046182. The cubic root of 66554550 is about 405.2527000908.

It can be divided in two parts, 6 and 6554550, that added together give a palindrome (6554556).

The spelling of 66554550 in words is "sixty-six million, five hundred fifty-four thousand, five hundred fifty".