2781389 has 4 divisors (see below), whose sum is σ = 2995356. Its totient is φ = 2567424.

The previous prime is 2781379. The next prime is 2781397. The reversal of 2781389 is 9831872.

2781389 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 354025 + 2427364 = 595^2 + 1558^2 .

It is a cyclic number.

It is not a de Polignac number, because 2781389 - 2⁸ = 2781133 is a prime.

It is a super-2 number, since 2×2781389² = 15472249538642, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2781329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106964 + ... + 106989.

It is an arithmetic number, because the mean of its divisors is an integer number (748839).

2^2781389 is an apocalyptic number.

It is an amenable number.

2781389 is a deficient number, since it is larger than the sum of its proper divisors (213967).

2781389 is a wasteful number, since it uses less digits than its factorization.

2781389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213966.

The product of its digits is 24192, while the sum is 38.

The square root of 2781389 is about 1667.7496814570. The cubic root of 2781389 is about 140.6330009604.

The spelling of 2781389 in words is "two million, seven hundred eighty-one thousand, three hundred eighty-nine".