28215647 has 4 divisors (see below), whose sum is σ = 28229976. Its totient is φ = 28201320.

The previous prime is 28215619. The next prime is 28215653. The reversal of 28215647 is 74651282.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74651282 = 2 ⋅37325641.

It is a cyclic number.

It is not a de Polignac number, because 28215647 - 2²² = 24021343 is a prime.

It is a super-2 number, since 2×28215647² = 1592245471257218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28215617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3629 + ... + 8342.

It is an arithmetic number, because the mean of its divisors is an integer number (7057494).

Almost surely, 2^28215647 is an apocalyptic number.

28215647 is a deficient number, since it is larger than the sum of its proper divisors (14329).

28215647 is a wasteful number, since it uses less digits than its factorization.

28215647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14328.

The product of its digits is 26880, while the sum is 35.

The square root of 28215647 is about 5311.8402649176. The cubic root of 28215647 is about 304.4364654711.

The spelling of 28215647 in words is "twenty-eight million, two hundred fifteen thousand, six hundred forty-seven".