221052906 has 48 divisors (see below), whose sum is σ = 502337160. Its totient is φ = 70156800.

The previous prime is 221052901. The next prime is 221052913. The reversal of 221052906 is 609250122.

It can be written as a sum of positive squares in 4 ways, for example, as 220968225 + 84681 = 14865^2 + 291^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 221052906.

It is not an unprimeable number, because it can be changed into a prime (221052901) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 35206 + ... + 41006.

Almost surely, 2^221052906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221052906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (251168580).

221052906 is an abundant number, since it is smaller than the sum of its proper divisors (281284254).

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

221052906 is a wasteful number, since it uses less digits than its factorization.

221052906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5911 (or 5908 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 221052906 is about 14867.8480621777. The cubic root of 221052906 is about 604.6426011051.

The spelling of 221052906 in words is "two hundred twenty-one million, fifty-two thousand, nine hundred six".