221261666 has 16 divisors (see below), whose sum is σ = 340810848. Its totient is φ = 107671200.

The previous prime is 221261641. The next prime is 221261687. The reversal of 221261666 is 666162122.

221261666 is digitally balanced in base 3, 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, 33281 + ... + 39371.

It is an arithmetic number, because the mean of its divisors is an integer number (21300678).

Almost surely, 2^221261666 is an apocalyptic number.

221261666 is a deficient number, since it is larger than the sum of its proper divisors (119549182).

221261666 is a wasteful number, since it uses less digits than its factorization.

221261666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6577.

The product of its digits is 10368, while the sum is 32.

The square root of 221261666 is about 14874.8669237745. The cubic root of 221261666 is about 604.8328805534.

The spelling of 221261666 in words is "two hundred twenty-one million, two hundred sixty-one thousand, six hundred sixty-six".