28993117 has 4 divisors (see below), whose sum is σ = 29468476. Its totient is φ = 28517760.

The previous prime is 28993103. The next prime is 28993141. The reversal of 28993117 is 71139982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71139982 = 2 ⋅35569991.

It can be written as a sum of positive squares in 2 ways, for example, as 16112196 + 12880921 = 4014^2 + 3589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28993117 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28993117.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28993147) 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, 237588 + ... + 237709.

It is an arithmetic number, because the mean of its divisors is an integer number (7367119).

Almost surely, 2^28993117 is an apocalyptic number.

It is an amenable number.

28993117 is a deficient number, since it is larger than the sum of its proper divisors (475359).

28993117 is an equidigital number, since it uses as much as digits as its factorization.

28993117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475358.

The product of its digits is 27216, while the sum is 40.

The square root of 28993117 is about 5384.5256987036. The cubic root of 28993117 is about 307.2073740284.

The spelling of 28993117 in words is "twenty-eight million, nine hundred ninety-three thousand, one hundred seventeen".