2099921 has 2 divisors, whose sum is σ = 2099922. Its totient is φ = 2099920.

The previous prime is 2099893. The next prime is 2099927. The reversal of 2099921 is 1299902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2016400 + 83521 = 1420^2 + 289^2 .

It is a cyclic number.

It is not a de Polignac number, because 2099921 - 2¹⁰ = 2098897 is a prime.

It is not a weakly prime, because it can be changed into another prime (2099927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1049960 + 1049961.

It is an arithmetic number, because the mean of its divisors is an integer number (1049961).

2^2099921 is an apocalyptic number.

It is an amenable number.

2099921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2099921 is an equidigital number, since it uses as much as digits as its factorization.

2099921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 2099921 is about 1449.1104167730. The cubic root of 2099921 is about 128.0563106730.

The spelling of 2099921 in words is "two million, ninety-nine thousand, nine hundred twenty-one".