28028005 has 8 divisors (see below), whose sum is σ = 33967224. Its totient is φ = 22200000.

The previous prime is 28027991. The next prime is 28028029. The reversal of 28028005 is 50082082.

It can be written as a sum of positive squares in 4 ways, for example, as 14122564 + 13905441 = 3758^2 + 3729^2 .

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

It is not a de Polignac number, because 28028005 - 2⁵ = 28027973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27246 + ... + 28255.

It is an arithmetic number, because the mean of its divisors is an integer number (4245903).

Almost surely, 2^28028005 is an apocalyptic number.

It is an amenable number.

28028005 is a deficient number, since it is larger than the sum of its proper divisors (5939219).

28028005 is a wasteful number, since it uses less digits than its factorization.

28028005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55607.

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 28028005 is about 5294.1481845524. The cubic root of 28028005 is about 303.7601011617.

The spelling of 28028005 in words is "twenty-eight million, twenty-eight thousand, five".