2112721 has 4 divisors (see below), whose sum is σ = 2275252. Its totient is φ = 1950192.

The previous prime is 2112713. The next prime is 2112727. The reversal of 2112721 is 1272112.

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 577600 + 1535121 = 760^2 + 1239^2 .

It is a cyclic number.

It is not a de Polignac number, because 2112721 - 2³ = 2112713 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2112695 and 2112704.

It is not an unprimeable number, because it can be changed into a prime (2112727) 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, 81246 + ... + 81271.

It is an arithmetic number, because the mean of its divisors is an integer number (568813).

2^2112721 is an apocalyptic number.

It is an amenable number.

2112721 is a deficient number, since it is larger than the sum of its proper divisors (162531).

2112721 is a wasteful number, since it uses less digits than its factorization.

2112721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162530.

The product of its digits is 56, while the sum is 16.

The square root of 2112721 is about 1453.5202096978. The cubic root of 2112721 is about 128.3159714898.

Adding to 2112721 its reverse (1272112), we get a palindrome (3384833).

The spelling of 2112721 in words is "two million, one hundred twelve thousand, seven hundred twenty-one".