55221666 has 16 divisors (see below), whose sum is σ = 115245504. Its totient is φ = 17606864.

The previous prime is 55221641. The next prime is 55221671. The reversal of 55221666 is 66612255.

It is a happy number.

55221666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199941 + ... + 200216.

It is an arithmetic number, because the mean of its divisors is an integer number (7202844).

Almost surely, 2^55221666 is an apocalyptic number.

55221666 is an abundant number, since it is smaller than the sum of its proper divisors (60023838).

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

55221666 is a wasteful number, since it uses less digits than its factorization.

55221666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400185.

The product of its digits is 21600, while the sum is 33.

The square root of 55221666 is about 7431.1281781436. The cubic root of 55221666 is about 380.8054614077.

The spelling of 55221666 in words is "fifty-five million, two hundred twenty-one thousand, six hundred sixty-six".