221001122212121 has 4 divisors (see below), whose sum is σ = 221110691436852. Its totient is φ = 220891552987392.

The previous prime is 221001122212081. The next prime is 221001122212127. The reversal of 221001122212121 is 121212221100122.

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 196463365538521 + 24537756673600 = 14016539^2 + 4953560^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221001122212121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221001122212093 and 221001122212102.

It is not an unprimeable number, because it can be changed into a prime (221001122212127) 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, 54784609340 + ... + 54784613373.

It is an arithmetic number, because the mean of its divisors is an integer number (55277672859213).

Almost surely, 2^{221001122212121} is an apocalyptic number.

It is an amenable number.

221001122212121 is a deficient number, since it is larger than the sum of its proper divisors (109569224731).

221001122212121 is a wasteful number, since it uses less digits than its factorization.

221001122212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109569224730.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 221001122212121 its reverse (121212221100122), we get a palindrome (342213343312243).

The spelling of 221001122212121 in words is "two hundred twenty-one trillion, one billion, one hundred twenty-two million, two hundred twelve thousand, one hundred twenty-one".