221561066 has 4 divisors (see below), whose sum is σ = 332341602. Its totient is φ = 110780532.

The previous prime is 221561057. The next prime is 221561077. The reversal of 221561066 is 660165122.

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

It can be written as a sum of positive squares in only one way, i.e., 130759225 + 90801841 = 11435^2 + 9529^2 .

It is a Curzon number.

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 as a sum of consecutive naturals, namely, 55390265 + ... + 55390268.

Almost surely, 2^221561066 is an apocalyptic number.

221561066 is a deficient number, since it is larger than the sum of its proper divisors (110780536).

221561066 is a wasteful number, since it uses less digits than its factorization.

221561066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110780535.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 221561066 is about 14884.9274771495. The cubic root of 221561066 is about 605.1055672624.

The spelling of 221561066 in words is "two hundred twenty-one million, five hundred sixty-one thousand, sixty-six".