28215717 has 16 divisors (see below), whose sum is σ = 38338560. Its totient is φ = 18455472.

The previous prime is 28215713. The next prime is 28215727. The reversal of 28215717 is 71751282.

It is not a de Polignac number, because 28215717 - 2² = 28215713 is a prime.

It is a super-2 number, since 2×28215717² = 1592253371648178, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28215713) 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 15 ways as a sum of consecutive naturals, for example, 38884 + ... + 39602.

It is an arithmetic number, because the mean of its divisors is an integer number (2396160).

Almost surely, 2^28215717 is an apocalyptic number.

It is an amenable number.

28215717 is a deficient number, since it is larger than the sum of its proper divisors (10122843).

28215717 is a wasteful number, since it uses less digits than its factorization.

28215717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 952.

The product of its digits is 7840, while the sum is 33.

The square root of 28215717 is about 5311.8468539671. The cubic root of 28215717 is about 304.4367172290.

Adding to 28215717 its reverse (71751282), we get a palindrome (99966999).

The spelling of 28215717 in words is "twenty-eight million, two hundred fifteen thousand, seven hundred seventeen".