2121121021121 has 4 divisors (see below), whose sum is σ = 2123214922452. Its totient is φ = 2119027119792.

The previous prime is 2121121021087. The next prime is 2121121021127. The reversal of 2121121021121 is 1211201211212.

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 682500690496 + 1438620330625 = 826136^2 + 1199425^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121121021121 - 2¹⁰ = 2121121020097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121121021121.

It is not an unprimeable number, because it can be changed into a prime (2121121021127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1046949146 + ... + 1046951171.

It is an arithmetic number, because the mean of its divisors is an integer number (530803730613).

Almost surely, 2^{2121121021121} is an apocalyptic number.

It is an amenable number.

2121121021121 is a deficient number, since it is larger than the sum of its proper divisors (2093901331).

2121121021121 is a wasteful number, since it uses less digits than its factorization.

2121121021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2093901330.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 2121121021121 its reverse (1211201211212), we get a palindrome (3332322232333).

The spelling of 2121121021121 in words is "two trillion, one hundred twenty-one billion, one hundred twenty-one million, twenty-one thousand, one hundred twenty-one".