28697993 has 2 divisors, whose sum is σ = 28697994. Its totient is φ = 28697992.

The previous prime is 28697959. The next prime is 28698011. The reversal of 28697993 is 39979682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28590409 + 107584 = 5347^2 + 328^2 .

It is a cyclic number.

It is not a de Polignac number, because 28697993 - 2⁸ = 28697737 is a prime.

It is not a weakly prime, because it can be changed into another prime (28697093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14348996 + 14348997.

It is an arithmetic number, because the mean of its divisors is an integer number (14348997).

Almost surely, 2^28697993 is an apocalyptic number.

It is an amenable number.

28697993 is a deficient number, since it is larger than the sum of its proper divisors (1).

28697993 is an equidigital number, since it uses as much as digits as its factorization.

28697993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1469664, while the sum is 53.

The square root of 28697993 is about 5357.0507744467. The cubic root of 28697993 is about 306.1614516732.

The spelling of 28697993 in words is "twenty-eight million, six hundred ninety-seven thousand, nine hundred ninety-three".