2123111021 has 4 divisors (see below), whose sum is σ = 2123340444. Its totient is φ = 2122881600.

The previous prime is 2123110993. The next prime is 2123111099. The reversal of 2123111021 is 1201113212.

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 15015625 + 2108095396 = 3875^2 + 45914^2 .

It is a cyclic number.

It is not a de Polignac number, because 2123111021 - 2¹⁰ = 2123109997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2123110987 and 2123111005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123111321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 100220 + ... + 119541.

It is an arithmetic number, because the mean of its divisors is an integer number (530835111).

Almost surely, 2^2123111021 is an apocalyptic number.

It is an amenable number.

2123111021 is a deficient number, since it is larger than the sum of its proper divisors (229423).

2123111021 is an equidigital number, since it uses as much as digits as its factorization.

2123111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229422.

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

The square root of 2123111021 is about 46077.2288771797. The cubic root of 2123111021 is about 1285.2597336156.

Adding to 2123111021 its reverse (1201113212), we get a palindrome (3324224233).

The spelling of 2123111021 in words is "two billion, one hundred twenty-three million, one hundred eleven thousand, twenty-one".