2120121221021 has 4 divisors (see below), whose sum is σ = 2120128220700. Its totient is φ = 2120114221344.

The previous prime is 2120121220913. The next prime is 2120121221041. The reversal of 2120121221021 is 1201221210212.

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 793676083225 + 1326445137796 = 890885^2 + 1151714^2 .

It is a cyclic number.

It is not a de Polignac number, because 2120121221021 - 2²² = 2120117026717 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 (2120121221041) 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, 3023936 + ... + 3658473.

It is an arithmetic number, because the mean of its divisors is an integer number (530032055175).

Almost surely, 2^{2120121221021} is an apocalyptic number.

It is an amenable number.

2120121221021 is a deficient number, since it is larger than the sum of its proper divisors (6999679).

2120121221021 is an equidigital number, since it uses as much as digits as its factorization.

2120121221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6999678.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 2120121221021 its reverse (1201221210212), we get a palindrome (3321342431233).

The spelling of 2120121221021 in words is "two trillion, one hundred twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, twenty-one".