28109566647 has 24 divisors (see below), whose sum is σ = 42820202880. Its totient is φ = 18422079480.

The previous prime is 28109566643. The next prime is 28109566763. The reversal of 28109566647 is 74666590182.

It is not a de Polignac number, because 28109566647 - 2² = 28109566643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28109566593 and 28109566602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28109566643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 965979 + ... + 994652.

It is an arithmetic number, because the mean of its divisors is an integer number (1784175120).

Almost surely, 2^28109566647 is an apocalyptic number.

28109566647 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

28109566647 is a deficient number, since it is larger than the sum of its proper divisors (14710636233).

28109566647 is an equidigital number, since it uses as much as digits as its factorization.

28109566647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1960705 (or 1960693 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 54.

The spelling of 28109566647 in words is "twenty-eight billion, one hundred nine million, five hundred sixty-six thousand, six hundred forty-seven".