28005478 has 4 divisors (see below), whose sum is σ = 42008220. Its totient is φ = 14002738.

The previous prime is 28005473. The next prime is 28005491. The reversal of 28005478 is 87450082.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28005473) 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 as a sum of consecutive naturals, namely, 7001368 + ... + 7001371.

It is an arithmetic number, because the mean of its divisors is an integer number (10502055).

Almost surely, 2^28005478 is an apocalyptic number.

28005478 is a deficient number, since it is larger than the sum of its proper divisors (14002742).

28005478 is a wasteful number, since it uses less digits than its factorization.

28005478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14002741.

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 28005478 is about 5292.0202191602. The cubic root of 28005478 is about 303.6786987944.

The spelling of 28005478 in words is "twenty-eight million, five thousand, four hundred seventy-eight".