221110001221 has 4 divisors (see below), whose sum is σ = 222232387212. Its totient is φ = 219987615232.

The previous prime is 221110001209. The next prime is 221110001257. The reversal of 221110001221 is 122100011122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 215074265121 + 6035736100 = 463761^2 + 77690^2 .

It is a cyclic number.

It is not a de Polignac number, because 221110001221 - 2¹³ = 221109993029 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 (221110001821) 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 3 ways as a sum of consecutive naturals, for example, 561192700 + ... + 561193093.

It is an arithmetic number, because the mean of its divisors is an integer number (55558096803).

Almost surely, 2^221110001221 is an apocalyptic number.

It is an amenable number.

221110001221 is a deficient number, since it is larger than the sum of its proper divisors (1122385991).

221110001221 is a wasteful number, since it uses less digits than its factorization.

221110001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122385990.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 221110001221 its reverse (122100011122), we get a palindrome (343210012343).

Subtracting from 221110001221 its reverse (122100011122), we obtain a palindrome (99009990099).

The spelling of 221110001221 in words is "two hundred twenty-one billion, one hundred ten million, one thousand, two hundred twenty-one".