2781005 has 8 divisors (see below), whose sum is σ = 3349752. Its totient is φ = 2216448.

The previous prime is 2781001. The next prime is 2781007. The reversal of 2781005 is 5001872.

It can be written as a sum of positive squares in 4 ways, for example, as 2116 + 2778889 = 46^2 + 1667^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2781005 - 2² = 2781001 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2781001) 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 7 ways as a sum of consecutive naturals, for example, 677 + ... + 2453.

It is an arithmetic number, because the mean of its divisors is an integer number (418719).

2^2781005 is an apocalyptic number.

It is an amenable number.

2781005 is a deficient number, since it is larger than the sum of its proper divisors (568747).

2781005 is a wasteful number, since it uses less digits than its factorization.

2781005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2095.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 2781005 is about 1667.6345522926. The cubic root of 2781005 is about 140.6265287077.

Adding to 2781005 its reverse (5001872), we get a palindrome (7782877).

The spelling of 2781005 in words is "two million, seven hundred eighty-one thousand, five".