2780909 has 2 divisors, whose sum is σ = 2780910. Its totient is φ = 2780908.

The previous prime is 2780891. The next prime is 2780923. The reversal of 2780909 is 9090872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2175625 + 605284 = 1475^2 + 778^2 .

It is a cyclic number.

It is not a de Polignac number, because 2780909 - 2²⁰ = 1732333 is a prime.

It is a Sophie Germain prime.

2780909 is a modest number, since divided by 909 gives 278 as remainder.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2780209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1390454 + 1390455.

It is an arithmetic number, because the mean of its divisors is an integer number (1390455).

2^2780909 is an apocalyptic number.

It is an amenable number.

2780909 is a deficient number, since it is larger than the sum of its proper divisors (1).

2780909 is an equidigital number, since it uses as much as digits as its factorization.

2780909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 2780909 is about 1667.6057687595. The cubic root of 2780909 is about 140.6249105514.

The spelling of 2780909 in words is "two million, seven hundred eighty thousand, nine hundred nine".