221505212 has 12 divisors (see below), whose sum is σ = 396649176. Its totient is φ = 108176880.

The previous prime is 221505209. The next prime is 221505217. The reversal of 221505212 is 212505122.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221505217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643739 + ... + 644082.

It is an arithmetic number, because the mean of its divisors is an integer number (33054098).

Almost surely, 2^221505212 is an apocalyptic number.

It is an amenable number.

221505212 is a deficient number, since it is larger than the sum of its proper divisors (175143964).

221505212 is a wasteful number, since it uses less digits than its factorization.

221505212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1287868 (or 1287866 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 221505212 is about 14883.0511656716. The cubic root of 221505212 is about 605.0547153575.

The spelling of 221505212 in words is "two hundred twenty-one million, five hundred five thousand, two hundred twelve".