2143123121 has 4 divisors (see below), whose sum is σ = 2145022500. Its totient is φ = 2141223744.

The previous prime is 2143123109. The next prime is 2143123127. The reversal of 2143123121 is 1213213412.

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 367680625 + 1775442496 = 19175^2 + 42136^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2143123121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2143123093 and 2143123102.

It is not an unprimeable number, because it can be changed into a prime (2143123127) 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, 947996 + ... + 950253.

It is an arithmetic number, because the mean of its divisors is an integer number (536255625).

Almost surely, 2^2143123121 is an apocalyptic number.

It is an amenable number.

2143123121 is a deficient number, since it is larger than the sum of its proper divisors (1899379).

2143123121 is a wasteful number, since it uses less digits than its factorization.

2143123121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1899378.

The product of its digits is 288, while the sum is 20.

The square root of 2143123121 is about 46293.8777917772. The cubic root of 2143123121 is about 1289.2853283539.

Adding to 2143123121 its reverse (1213213412), we get a palindrome (3356336533).

The spelling of 2143123121 in words is "two billion, one hundred forty-three million, one hundred twenty-three thousand, one hundred twenty-one".