28891647 has 20 divisors (see below), whose sum is σ = 45433080. Its totient is φ = 18246384.

The previous prime is 28891633. The next prime is 28891669. The reversal of 28891647 is 74619882.

It is not a de Polignac number, because 28891647 - 2⁴ = 28891631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28891607) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7848 + ... + 10925.

It is an arithmetic number, because the mean of its divisors is an integer number (2271654).

Almost surely, 2^28891647 is an apocalyptic number.

28891647 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

28891647 is a deficient number, since it is larger than the sum of its proper divisors (16541433).

28891647 is a wasteful number, since it uses less digits than its factorization.

28891647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18804 (or 18795 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 28891647 is about 5375.0950689267. The cubic root of 28891647 is about 306.8485673880.

The spelling of 28891647 in words is "twenty-eight million, eight hundred ninety-one thousand, six hundred forty-seven".