2780409 has 4 divisors (see below), whose sum is σ = 3707216. Its totient is φ = 1853604.

The previous prime is 2780399. The next prime is 2780413. The reversal of 2780409 is 9040872.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2780409 - 2⁸ = 2780153 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2780419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 463399 + ... + 463404.

It is an arithmetic number, because the mean of its divisors is an integer number (926804).

2^2780409 is an apocalyptic number.

It is an amenable number.

2780409 is a deficient number, since it is larger than the sum of its proper divisors (926807).

2780409 is an equidigital number, since it uses as much as digits as its factorization.

2780409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 926806.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 2780409 is about 1667.4558464919. The cubic root of 2780409 is about 140.6164820520.

The spelling of 2780409 in words is "two million, seven hundred eighty thousand, four hundred nine".