66227221 has 4 divisors (see below), whose sum is σ = 66511692. Its totient is φ = 65942752.

The previous prime is 66227219. The next prime is 66227297. The reversal of 66227221 is 12272266.

66227221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15888196 + 50339025 = 3986^2 + 7095^2 .

It is a cyclic number.

It is not a de Polignac number, because 66227221 - 2¹ = 66227219 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66227221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66227321) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 141886 + ... + 142351.

It is an arithmetic number, because the mean of its divisors is an integer number (16627923).

Almost surely, 2^66227221 is an apocalyptic number.

It is an amenable number.

66227221 is a deficient number, since it is larger than the sum of its proper divisors (284471).

66227221 is a wasteful number, since it uses less digits than its factorization.

66227221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284470.

The product of its digits is 4032, while the sum is 28.

The square root of 66227221 is about 8138.0108749006. The cubic root of 66227221 is about 404.5872358189.

Adding to 66227221 its reverse (12272266), we get a palindrome (78499487).

The spelling of 66227221 in words is "sixty-six million, two hundred twenty-seven thousand, two hundred twenty-one".