28928993 has 4 divisors (see below), whose sum is σ = 29002260. Its totient is φ = 28855728.

The previous prime is 28928957. The next prime is 28929023. The reversal of 28928993 is 39982982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21049744 + 7879249 = 4588^2 + 2807^2 .

It is a cyclic number.

It is not a de Polignac number, because 28928993 - 2²⁰ = 27880417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28928953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36038 + ... + 36831.

It is an arithmetic number, because the mean of its divisors is an integer number (7250565).

Almost surely, 2^28928993 is an apocalyptic number.

It is an amenable number.

28928993 is a deficient number, since it is larger than the sum of its proper divisors (73267).

28928993 is an equidigital number, since it uses as much as digits as its factorization.

28928993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73266.

The product of its digits is 559872, while the sum is 50.

The square root of 28928993 is about 5378.5679320801. The cubic root of 28928993 is about 306.9807236073.

The spelling of 28928993 in words is "twenty-eight million, nine hundred twenty-eight thousand, nine hundred ninety-three".