221666256290 has 16 divisors (see below), whose sum is σ = 412757857080. Its totient is φ = 85609036800.

The previous prime is 221666256241. The next prime is 221666256347. The reversal of 221666256290 is 92652666122.

221666256290 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 143564452201 + 78101804089 = 378899^2 + 279467^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 382182911 + ... + 382183490.

Almost surely, 2^221666256290 is an apocalyptic number.

221666256290 is a deficient number, since it is larger than the sum of its proper divisors (191091600790).

221666256290 is a wasteful number, since it uses less digits than its factorization.

221666256290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 764366437.

The product of its (nonzero) digits is 933120, while the sum is 47.

The spelling of 221666256290 in words is "two hundred twenty-one billion, six hundred sixty-six million, two hundred fifty-six thousand, two hundred ninety".