28775647 has 4 divisors (see below), whose sum is σ = 28815120. Its totient is φ = 28736176.

The previous prime is 28775597. The next prime is 28775653. The reversal of 28775647 is 74657782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74657782 = 2 ⋅37328891.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28775647 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28775597 and 28775606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28775687) 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, 18622 + ... + 20107.

It is an arithmetic number, because the mean of its divisors is an integer number (7203780).

Almost surely, 2^28775647 is an apocalyptic number.

28775647 is a deficient number, since it is larger than the sum of its proper divisors (39473).

28775647 is an equidigital number, since it uses as much as digits as its factorization.

28775647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39472.

The product of its digits is 658560, while the sum is 46.

The square root of 28775647 is about 5364.2937093340. The cubic root of 28775647 is about 306.4373507528.

The spelling of 28775647 in words is "twenty-eight million, seven hundred seventy-five thousand, six hundred forty-seven".