221012221 has 4 divisors (see below), whose sum is σ = 230621472. Its totient is φ = 211402972.

The previous prime is 221012201. The next prime is 221012227. The reversal of 221012221 is 122210122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221012221 - 2⁹ = 221011709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221012227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4804591 + ... + 4804636.

It is an arithmetic number, because the mean of its divisors is an integer number (57655368).

Almost surely, 2^221012221 is an apocalyptic number.

It is an amenable number.

221012221 is a deficient number, since it is larger than the sum of its proper divisors (9609251).

221012221 is an equidigital number, since it uses as much as digits as its factorization.

221012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9609250.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 221012221 is about 14866.4797783470. The cubic root of 221012221 is about 604.6055038116.

Adding to 221012221 its reverse (122210122), we get a palindrome (343222343).

The spelling of 221012221 in words is "two hundred twenty-one million, twelve thousand, two hundred twenty-one".