12728505 has 8 divisors (see below), whose sum is σ = 20365632. Its totient is φ = 6788528.

The previous prime is 12728503. The next prime is 12728509. The reversal of 12728505 is 50582721.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12728505 - 2¹ = 12728503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12728503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 424269 + ... + 424298.

It is an arithmetic number, because the mean of its divisors is an integer number (2545704).

Almost surely, 2^12728505 is an apocalyptic number.

12728505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12728505 is a deficient number, since it is larger than the sum of its proper divisors (7637127).

12728505 is an equidigital number, since it uses as much as digits as its factorization.

12728505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848575.

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 12728505 is about 3567.7030425752. The cubic root of 12728505 is about 233.4850792967.

Adding to 12728505 its sum of digits (30), we get a triangular number (12728535 = T₅₀₄₅).

The spelling of 12728505 in words is "twelve million, seven hundred twenty-eight thousand, five hundred five".