28673647 has 4 divisors (see below), whose sum is σ = 29340520. Its totient is φ = 28006776.

The previous prime is 28673639. The next prime is 28673653. The reversal of 28673647 is 74637682.

It is a happy number.

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 28673647 - 2³ = 28673639 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 666829 = 28673647 / (2 + 8 + 6 + 7 + 3 + 6 + 4 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28673627) 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, 333372 + ... + 333457.

It is an arithmetic number, because the mean of its divisors is an integer number (7335130).

Almost surely, 2^28673647 is an apocalyptic number.

28673647 is a deficient number, since it is larger than the sum of its proper divisors (666873).

28673647 is an equidigital number, since it uses as much as digits as its factorization.

28673647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666872.

The product of its digits is 338688, while the sum is 43.

The square root of 28673647 is about 5354.7779599158. Note that the first 3 decimals coincide. The cubic root of 28673647 is about 306.0748496181.

The spelling of 28673647 in words is "twenty-eight million, six hundred seventy-three thousand, six hundred forty-seven".