28188445 has 4 divisors (see below), whose sum is σ = 33826140. Its totient is φ = 22550752.

The previous prime is 28188427. The next prime is 28188463. The reversal of 28188445 is 54488182.

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

It is an interprime number because it is at equal distance from previous prime (28188427) and next prime (28188463).

It can be written as a sum of positive squares in 2 ways, for example, as 3218436 + 24970009 = 1794^2 + 4997^2 .

It is a cyclic number.

It is not a de Polignac number, because 28188445 - 2⁹ = 28187933 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28188398 and 28188407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2818840 + ... + 2818849.

It is an arithmetic number, because the mean of its divisors is an integer number (8456535).

Almost surely, 2^28188445 is an apocalyptic number.

It is an amenable number.

28188445 is a deficient number, since it is larger than the sum of its proper divisors (5637695).

28188445 is an equidigital number, since it uses as much as digits as its factorization.

28188445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5637694.

The product of its digits is 81920, while the sum is 40.

The square root of 28188445 is about 5309.2791412771. The cubic root of 28188445 is about 304.3386008192.

The spelling of 28188445 in words is "twenty-eight million, one hundred eighty-eight thousand, four hundred forty-five".