28758181 has 2 divisors, whose sum is σ = 28758182. Its totient is φ = 28758180.

The previous prime is 28758167. The next prime is 28758187. The reversal of 28758181 is 18185782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28408900 + 349281 = 5330^2 + 591^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28758181 is a prime.

It is a super-2 number, since 2×28758181² = 1654065948857522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28758187) 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 as a sum of consecutive naturals, namely, 14379090 + 14379091.

It is an arithmetic number, because the mean of its divisors is an integer number (14379091).

Almost surely, 2^28758181 is an apocalyptic number.

It is an amenable number.

28758181 is a deficient number, since it is larger than the sum of its proper divisors (1).

28758181 is an equidigital number, since it uses as much as digits as its factorization.

28758181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35840, while the sum is 40.

The square root of 28758181 is about 5362.6654753024. The cubic root of 28758181 is about 306.3753386167.

The spelling of 28758181 in words is "twenty-eight million, seven hundred fifty-eight thousand, one hundred eighty-one".