28727217 has 12 divisors (see below), whose sum is σ = 43032080. Its totient is φ = 19151316.

The previous prime is 28727191. The next prime is 28727233. The reversal of 28727217 is 71272782.

It is not a de Polignac number, because 28727217 - 2⁸ = 28726961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28727267) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58867 + ... + 59352.

Almost surely, 2^28727217 is an apocalyptic number.

28727217 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

28727217 is a deficient number, since it is larger than the sum of its proper divisors (14304863).

28727217 is an equidigital number, since it uses as much as digits as its factorization.

28727217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118234 (or 118222 counting only the distinct ones).

The product of its digits is 21952, while the sum is 36.

The square root of 28727217 is about 5359.7777006141. Note that the first 4 decimals coincide. The cubic root of 28727217 is about 306.2653407837.

Adding to 28727217 its reverse (71272782), we get a palindrome (99999999).

The spelling of 28727217 in words is "twenty-eight million, seven hundred twenty-seven thousand, two hundred seventeen".