2123120021 has 32 divisors (see below), whose sum is σ = 2588267520. Its totient is φ = 1716422400.

The previous prime is 2123120017. The next prime is 2123120047. The reversal of 2123120021 is 1200213212.

It is a happy number.

It is not a de Polignac number, because 2123120021 - 2² = 2123120017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2123119978 and 2123120005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123120081) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2241470 + ... + 2242416.

It is an arithmetic number, because the mean of its divisors is an integer number (80883360).

Almost surely, 2^2123120021 is an apocalyptic number.

It is an amenable number.

2123120021 is a deficient number, since it is larger than the sum of its proper divisors (465147499).

2123120021 is a wasteful number, since it uses less digits than its factorization.

2123120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1625.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 2123120021 is about 46077.3265391993. The cubic root of 2123120021 is about 1285.2615497117.

Adding to 2123120021 its reverse (1200213212), we get a palindrome (3323333233).

The spelling of 2123120021 in words is "two billion, one hundred twenty-three million, one hundred twenty thousand, twenty-one".