28020917 has 4 divisors (see below), whose sum is σ = 28704396. Its totient is φ = 27337440.

The previous prime is 28020911. The next prime is 28020961. The reversal of 28020917 is 71902082.

It is a happy number.

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 5827396 + 22193521 = 2414^2 + 4711^2 .

It is a cyclic number.

It is not a de Polignac number, because 28020917 - 2⁴ = 28020901 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 28020917.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28020911) 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 in 3 ways as a sum of consecutive naturals, for example, 341678 + ... + 341759.

It is an arithmetic number, because the mean of its divisors is an integer number (7176099).

Almost surely, 2^28020917 is an apocalyptic number.

It is an amenable number.

28020917 is a deficient number, since it is larger than the sum of its proper divisors (683479).

28020917 is an equidigital number, since it uses as much as digits as its factorization.

28020917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683478.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 28020917 is about 5293.4787238639. The cubic root of 28020917 is about 303.7344930468.

Adding to 28020917 its reverse (71902082), we get a palindrome (99922999).

The spelling of 28020917 in words is "twenty-eight million, twenty thousand, nine hundred seventeen".