28647639 has 6 divisors (see below), whose sum is σ = 41379936. Its totient is φ = 19098420.

The previous prime is 28647637. The next prime is 28647667. The reversal of 28647639 is 93674682.

28647639 is a `hidden beast` number, since 2 + 8 + 6 + 4 + 7 + 639 = 666.

It is not a de Polignac number, because 28647639 - 2¹ = 28647637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28647594 and 28647603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28647631) 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 5 ways as a sum of consecutive naturals, for example, 1591527 + ... + 1591544.

It is an arithmetic number, because the mean of its divisors is an integer number (6896656).

Almost surely, 2^28647639 is an apocalyptic number.

28647639 is a deficient number, since it is larger than the sum of its proper divisors (12732297).

28647639 is a wasteful number, since it uses less digits than its factorization.

28647639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3183077 (or 3183074 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The square root of 28647639 is about 5352.3489236035. The cubic root of 28647639 is about 305.9822814295.

The spelling of 28647639 in words is "twenty-eight million, six hundred forty-seven thousand, six hundred thirty-nine".