221221011 has 16 divisors (see below), whose sum is σ = 322253568. Its totient is φ = 133874400.

The previous prime is 221220997. The next prime is 221221037. The reversal of 221221011 is 110122122.

221221011 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221221011 - 2⁶ = 221220947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221221081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19381 + ... + 28601.

It is an arithmetic number, because the mean of its divisors is an integer number (20140848).

Almost surely, 2^221221011 is an apocalyptic number.

221221011 is a deficient number, since it is larger than the sum of its proper divisors (101032557).

221221011 is a wasteful number, since it uses less digits than its factorization.

221221011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9962.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 221221011 is about 14873.5002941473. The cubic root of 221221011 is about 604.7958339389.

Adding to 221221011 its reverse (110122122), we get a palindrome (331343133).

The spelling of 221221011 in words is "two hundred twenty-one million, two hundred twenty-one thousand, eleven".