221001022121221 has 16 divisors (see below), whose sum is σ = 231222090188160. Its totient is φ = 210831719503680.

The previous prime is 221001022121203. The next prime is 221001022121261. The reversal of 221001022121221 is 122121220100122.

It is not a de Polignac number, because 221001022121221 - 2²⁵ = 221000988566789 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 (221001022121261) 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, 4788351 + ... + 21562243.

It is an arithmetic number, because the mean of its divisors is an integer number (14451380636760).

Almost surely, 2^{221001022121221} is an apocalyptic number.

It is an amenable number.

221001022121221 is a deficient number, since it is larger than the sum of its proper divisors (10221068066939).

221001022121221 is a wasteful number, since it uses less digits than its factorization.

221001022121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16775436.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 221001022121221 its reverse (122121220100122), we get a palindrome (343122242221343).

The spelling of 221001022121221 in words is "two hundred twenty-one trillion, one billion, twenty-two million, one hundred twenty-one thousand, two hundred twenty-one".