28081913 has 2 divisors, whose sum is σ = 28081914. Its totient is φ = 28081912.

The previous prime is 28081901. The next prime is 28081951. The reversal of 28081913 is 31918082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27321529 + 760384 = 5227^2 + 872^2 .

It is a cyclic number.

It is not a de Polignac number, because 28081913 - 2⁴ = 28081897 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28081913.

It is not a weakly prime, because it can be changed into another prime (28081973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14040956 + 14040957.

It is an arithmetic number, because the mean of its divisors is an integer number (14040957).

Almost surely, 2^28081913 is an apocalyptic number.

It is an amenable number.

28081913 is a deficient number, since it is larger than the sum of its proper divisors (1).

28081913 is an equidigital number, since it uses as much as digits as its factorization.

28081913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 28081913 is about 5299.2370205531. The cubic root of 28081913 is about 303.9547233182.

Adding to 28081913 its reverse (31918082), we get a palindrome (59999995).

The spelling of 28081913 in words is "twenty-eight million, eighty-one thousand, nine hundred thirteen".