121220212121021 has 16 divisors (see below), whose sum is σ = 130806523738800. Its totient is φ = 111671467622400.

The previous prime is 121220212120937. The next prime is 121220212121023. The reversal of 121220212121021 is 120121212022121.

It can be written as a sum of positive squares in 8 ways, for example, as 361213020100 + 120858999100921 = 601010^2 + 10993589^2 .

It is a cyclic number.

It is not a de Polignac number, because 121220212121021 - 2³⁸ = 120945334214077 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 121220212120984 and 121220212121002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121220212121023) 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, 11955005 + ... + 19630653.

It is an arithmetic number, because the mean of its divisors is an integer number (8175407733675).

Almost surely, 2^{121220212121021} is an apocalyptic number.

It is an amenable number.

121220212121021 is a deficient number, since it is larger than the sum of its proper divisors (9586311617779).

121220212121021 is a wasteful number, since it uses less digits than its factorization.

121220212121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7678096.

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

Adding to 121220212121021 its reverse (120121212022121), we get a palindrome (241341424143142).

The spelling of 121220212121021 in words is "one hundred twenty-one trillion, two hundred twenty billion, two hundred twelve million, one hundred twenty-one thousand, twenty-one".