2155409 has 2 divisors, whose sum is σ = 2155410. Its totient is φ = 2155408.

The previous prime is 2155397. The next prime is 2155423. The reversal of 2155409 is 9045512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1849600 + 305809 = 1360^2 + 553^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155409 - 2⁴ = 2155393 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a zygodrome in base 3.

It is not a weakly prime, because it can be changed into another prime (2155429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1077704 + 1077705.

It is an arithmetic number, because the mean of its divisors is an integer number (1077705).

2^2155409 is an apocalyptic number.

It is an amenable number.

2155409 is a deficient number, since it is larger than the sum of its proper divisors (1).

2155409 is an equidigital number, since it uses as much as digits as its factorization.

2155409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 2155409 is about 1468.1311249340. The cubic root of 2155409 is about 129.1744330167.

The spelling of 2155409 in words is "two million, one hundred fifty-five thousand, four hundred nine".