28217247 has 4 divisors (see below), whose sum is σ = 37623000. Its totient is φ = 18811496.

The previous prime is 28217243. The next prime is 28217257. The reversal of 28217247 is 74271282.

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

It is a cyclic number.

It is not a de Polignac number, because 28217247 - 2² = 28217243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28217243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4702872 + ... + 4702877.

It is an arithmetic number, because the mean of its divisors is an integer number (9405750).

Almost surely, 2^28217247 is an apocalyptic number.

28217247 is a deficient number, since it is larger than the sum of its proper divisors (9405753).

28217247 is an equidigital number, since it uses as much as digits as its factorization.

28217247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9405752.

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

The square root of 28217247 is about 5311.9908697211. The cubic root of 28217247 is about 304.4422198331.

The spelling of 28217247 in words is "twenty-eight million, two hundred seventeen thousand, two hundred forty-seven".