121111222021221 has 4 divisors (see below), whose sum is σ = 161481629361632. Its totient is φ = 80740814680812.

The previous prime is 121111222021151. The next prime is 121111222021241. The reversal of 121111222021221 is 122120222111121.

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 not a de Polignac number, because 121111222021221 - 2¹⁰ = 121111222020197 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 (121111222021241) 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, 20185203670201 + ... + 20185203670206.

It is an arithmetic number, because the mean of its divisors is an integer number (40370407340408).

Almost surely, 2^{121111222021221} is an apocalyptic number.

It is an amenable number.

121111222021221 is a deficient number, since it is larger than the sum of its proper divisors (40370407340411).

121111222021221 is an equidigital number, since it uses as much as digits as its factorization.

121111222021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40370407340410.

The product of its (nonzero) digits is 128, while the sum is 21.

Adding to 121111222021221 its reverse (122120222111121), we get a palindrome (243231444132342).

The spelling of 121111222021221 in words is "one hundred twenty-one trillion, one hundred eleven billion, two hundred twenty-two million, twenty-one thousand, two hundred twenty-one".