2780009 has 4 divisors (see below), whose sum is σ = 2832516. Its totient is φ = 2727504.

The previous prime is 2779991. The next prime is 2780039. The reversal of 2780009 is 9000872.

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 1570009 + 1210000 = 1253^2 + 1100^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2780009 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2780009.

It is not an unprimeable number, because it can be changed into a prime (2780039) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26174 + ... + 26279.

It is an arithmetic number, because the mean of its divisors is an integer number (708129).

2^2780009 is an apocalyptic number.

It is an amenable number.

2780009 is a deficient number, since it is larger than the sum of its proper divisors (52507).

2780009 is an equidigital number, since it uses as much as digits as its factorization.

2780009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52506.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 2780009 is about 1667.3358989718. The cubic root of 2780009 is about 140.6097385249.

The spelling of 2780009 in words is "two million, seven hundred eighty thousand, nine".