2111106721 has 4 divisors (see below), whose sum is σ = 2111245444. Its totient is φ = 2110968000.

The previous prime is 2111106719. The next prime is 2111106749. The reversal of 2111106721 is 1276011112.

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 1477326096 + 633780625 = 38436^2 + 25175^2 .

It is a cyclic number.

It is not a de Polignac number, because 2111106721 - 2¹ = 2111106719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2111106692 and 2111106701.

It is not an unprimeable number, because it can be changed into a prime (2111106791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43260 + ... + 78061.

It is an arithmetic number, because the mean of its divisors is an integer number (527811361).

Almost surely, 2^2111106721 is an apocalyptic number.

It is an amenable number.

2111106721 is a deficient number, since it is larger than the sum of its proper divisors (138723).

2111106721 is a wasteful number, since it uses less digits than its factorization.

2111106721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138722.

The product of its (nonzero) digits is 168, while the sum is 22.

The square root of 2111106721 is about 45946.7813997890. The cubic root of 2111106721 is about 1282.8328211962.

Adding to 2111106721 its reverse (1276011112), we get a palindrome (3387117833).

The spelling of 2111106721 in words is "two billion, one hundred eleven million, one hundred six thousand, seven hundred twenty-one".