28040447 has 4 divisors (see below), whose sum is σ = 29516280. Its totient is φ = 26564616.

The previous prime is 28040443. The next prime is 28040449. The reversal of 28040447 is 74404082.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28040447 - 2² = 28040443 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28040443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 737888 + ... + 737925.

It is an arithmetic number, because the mean of its divisors is an integer number (7379070).

Almost surely, 2^28040447 is an apocalyptic number.

28040447 is a deficient number, since it is larger than the sum of its proper divisors (1475833).

28040447 is a wasteful number, since it uses less digits than its factorization.

28040447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1475832.

The product of its (nonzero) digits is 7168, while the sum is 29.

The square root of 28040447 is about 5295.3231251738. The cubic root of 28040447 is about 303.8050422136.

Subtracting 28040447 from its reverse (74404082), we obtain a triangular number (46363635 = T₉₆₂₉).

The spelling of 28040447 in words is "twenty-eight million, forty thousand, four hundred forty-seven".