2728181 has 4 divisors (see below), whose sum is σ = 2794764. Its totient is φ = 2661600.

The previous prime is 2728171. The next prime is 2728199. The reversal of 2728181 is 1818272.

2728181 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 1188100 + 1540081 = 1090^2 + 1241^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2728181 is a prime.

It is a super-2 number, since 2×2728181² = 14885943137522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2728171) 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, 33230 + ... + 33311.

It is an arithmetic number, because the mean of its divisors is an integer number (698691).

2^2728181 is an apocalyptic number.

It is an amenable number.

2728181 is a deficient number, since it is larger than the sum of its proper divisors (66583).

2728181 is an equidigital number, since it uses as much as digits as its factorization.

2728181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66582.

The product of its digits is 1792, while the sum is 29.

The square root of 2728181 is about 1651.7206180223. The cubic root of 2728181 is about 139.7304507437.

Subtracting from 2728181 its reverse (1818272), we obtain a palindrome (909909).

The spelling of 2728181 in words is "two million, seven hundred twenty-eight thousand, one hundred eighty-one".