28019993 has 2 divisors, whose sum is σ = 28019994. Its totient is φ = 28019992.

The previous prime is 28019977. The next prime is 28020023. The reversal of 28019993 is 39991082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21603904 + 6416089 = 4648^2 + 2533^2 .

It is a cyclic number.

It is not a de Polignac number, because 28019993 - 2⁴ = 28019977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28019993.

It is not a weakly prime, because it can be changed into another prime (28019293) 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, 14009996 + 14009997.

It is an arithmetic number, because the mean of its divisors is an integer number (14009997).

Almost surely, 2^28019993 is an apocalyptic number.

It is an amenable number.

28019993 is a deficient number, since it is larger than the sum of its proper divisors (1).

28019993 is an equidigital number, since it uses as much as digits as its factorization.

28019993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 28019993 is about 5293.3914459447. The cubic root of 28019993 is about 303.7311544247.

The spelling of 28019993 in words is "twenty-eight million, nineteen thousand, nine hundred ninety-three".