221020121221 has 4 divisors (see below), whose sum is σ = 232652759200. Its totient is φ = 209387483244.

The previous prime is 221020121219. The next prime is 221020121233. The reversal of 221020121221 is 122121020122.

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 221020121221 - 2¹ = 221020121219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221020121195 and 221020121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221020221221) 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, 5816318961 + ... + 5816318998.

It is an arithmetic number, because the mean of its divisors is an integer number (58163189800).

Almost surely, 2^221020121221 is an apocalyptic number.

It is an amenable number.

221020121221 is a deficient number, since it is larger than the sum of its proper divisors (11632637979).

221020121221 is a wasteful number, since it uses less digits than its factorization.

221020121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11632637978.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221020121221 its reverse (122121020122), we get a palindrome (343141141343).

The spelling of 221020121221 in words is "two hundred twenty-one billion, twenty million, one hundred twenty-one thousand, two hundred twenty-one".