221221120222001 has 4 divisors (see below), whose sum is σ = 221221334044452. Its totient is φ = 221220906399552.

The previous prime is 221221120221989. The next prime is 221221120222019. The reversal of 221221120222001 is 100222021122122.

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 218625796000000 + 2595324222001 = 14786000^2 + 1611001^2 .

It is a cyclic number.

It is not a de Polignac number, because 221221120222001 - 2¹⁰ = 221221120220977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221221120222031) 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, 105351740 + ... + 107431053.

It is an arithmetic number, because the mean of its divisors is an integer number (55305333511113).

Almost surely, 2^{221221120222001} is an apocalyptic number.

It is an amenable number.

221221120222001 is a deficient number, since it is larger than the sum of its proper divisors (213822451).

221221120222001 is a wasteful number, since it uses less digits than its factorization.

221221120222001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213822450.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 221221120222001 its reverse (100222021122122), we get a palindrome (321443141344123).

The spelling of 221221120222001 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, one hundred twenty million, two hundred twenty-two thousand, one".