2121131021 has 16 divisors (see below), whose sum is σ = 2325821040. Its totient is φ = 1925468160.

The previous prime is 2121131003. The next prime is 2121131053. The reversal of 2121131021 is 1201311212.

It can be written as a sum of positive squares in 8 ways, for example, as 702780100 + 1418350921 = 26510^2 + 37661^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121131021 - 2³⁰ = 1047389197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2121130987 and 2121131005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121134021) 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, 649625 + ... + 652881.

It is an arithmetic number, because the mean of its divisors is an integer number (145363815).

Almost surely, 2^2121131021 is an apocalyptic number.

It is an amenable number.

2121131021 is a deficient number, since it is larger than the sum of its proper divisors (204690019).

2121131021 is a wasteful number, since it uses less digits than its factorization.

2121131021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4624.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 2121131021 is about 46055.7381984048. The cubic root of 2121131021 is about 1284.8600676301.

Adding to 2121131021 its reverse (1201311212), we get a palindrome (3322442233).

The spelling of 2121131021 in words is "two billion, one hundred twenty-one million, one hundred thirty-one thousand, twenty-one".