28221747 has 4 divisors (see below), whose sum is σ = 37629000. Its totient is φ = 18814496.

The previous prime is 28221737. The next prime is 28221757. The reversal of 28221747 is 74712282.

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 (28221737) and next prime (28221757).

It is a cyclic number.

It is not a de Polignac number, because 28221747 - 2¹¹ = 28219699 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28221737) 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, 4703622 + ... + 4703627.

It is an arithmetic number, because the mean of its divisors is an integer number (9407250).

Almost surely, 2^28221747 is an apocalyptic number.

28221747 is a deficient number, since it is larger than the sum of its proper divisors (9407253).

28221747 is an equidigital number, since it uses as much as digits as its factorization.

28221747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9407252.

The product of its digits is 12544, while the sum is 33.

The square root of 28221747 is about 5312.4144228401. The cubic root of 28221747 is about 304.4584028100.

The spelling of 28221747 in words is "twenty-eight million, two hundred twenty-one thousand, seven hundred forty-seven".