28181911 has 2 divisors, whose sum is σ = 28181912. Its totient is φ = 28181910.

The previous prime is 28181897. The next prime is 28181941. The reversal of 28181911 is 11918182.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28181911 - 2⁹ = 28181399 is a prime.

It is a super-2 number, since 2×28181911² = 1588440215223842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28181941) 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, 14090955 + 14090956.

It is an arithmetic number, because the mean of its divisors is an integer number (14090956).

Almost surely, 2^28181911 is an apocalyptic number.

28181911 is a deficient number, since it is larger than the sum of its proper divisors (1).

28181911 is an equidigital number, since it uses as much as digits as its factorization.

28181911 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 31.

The square root of 28181911 is about 5308.6637678421. The cubic root of 28181911 is about 304.3150840663.

It can be divided in two parts, 28181 and 911, that added together give a palindrome (29092).

The spelling of 28181911 in words is "twenty-eight million, one hundred eighty-one thousand, nine hundred eleven".