2123909 has 2 divisors, whose sum is σ = 2123910. Its totient is φ = 2123908.

The previous prime is 2123897. The next prime is 2123917. The reversal of 2123909 is 9093212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1876900 + 247009 = 1370^2 + 497^2 .

It is a cyclic number.

It is not a de Polignac number, because 2123909 - 2¹⁶ = 2058373 is a prime.

It is a super-3 number, since 3×2123909³ = 28742793213353335287, which contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2123939) 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, 1061954 + 1061955.

It is an arithmetic number, because the mean of its divisors is an integer number (1061955).

2^2123909 is an apocalyptic number.

It is an amenable number.

2123909 is a deficient number, since it is larger than the sum of its proper divisors (1).

2123909 is an equidigital number, since it uses as much as digits as its factorization.

2123909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 2123909 is about 1457.3637157553. The cubic root of 2123909 is about 128.5420736628.

The spelling of 2123909 in words is "two million, one hundred twenty-three thousand, nine hundred nine".