1001121212221 has 16 divisors (see below), whose sum is σ = 1125046266624. Its totient is φ = 883901297664.

The previous prime is 1001121212171. The next prime is 1001121212227. The reversal of 1001121212221 is 1222121211001.

It is a cyclic number.

It is not a de Polignac number, because 1001121212221 - 2¹⁵ = 1001121179453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1001121212195 and 1001121212204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001121212227) 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, 12955120 + ... + 13032166.

It is an arithmetic number, because the mean of its divisors is an integer number (70315391664).

Almost surely, 2^{1001121212221} is an apocalyptic number.

It is an amenable number.

1001121212221 is a deficient number, since it is larger than the sum of its proper divisors (123925054403).

1001121212221 is a wasteful number, since it uses less digits than its factorization.

1001121212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120540.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1001121212221 its reverse (1222121211001), we get a palindrome (2223242423222).

The spelling of 1001121212221 in words is "one trillion, one billion, one hundred twenty-one million, two hundred twelve thousand, two hundred twenty-one".