221111221221 has 48 divisors (see below), whose sum is σ = 349748036352. Its totient is φ = 133496092800.

The previous prime is 221111221213. The next prime is 221111221231. The reversal of 221111221221 is 122122111122.

221111221221 is a `hidden beast` number, since 2 + 211 + 11 + 221 + 221 = 666.

It is not a de Polignac number, because 221111221221 - 2³ = 221111221213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221111221194 and 221111221203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221111221231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 32214436 + ... + 32221298.

It is an arithmetic number, because the mean of its divisors is an integer number (7286417424).

Almost surely, 2^221111221221 is an apocalyptic number.

It is an amenable number.

221111221221 is a deficient number, since it is larger than the sum of its proper divisors (128636815131).

221111221221 is a wasteful number, since it uses less digits than its factorization.

221111221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8074 (or 8071 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 221111221221 its reverse (122122111122), we get a palindrome (343233332343).

It can be divided in two parts, 22111122 and 1221, that multiplied together give a palindrome (26997679962).

The spelling of 221111221221 in words is "two hundred twenty-one billion, one hundred eleven million, two hundred twenty-one thousand, two hundred twenty-one".