28158005 has 4 divisors (see below), whose sum is σ = 33789612. Its totient is φ = 22526400.

The previous prime is 28157993. The next prime is 28158017. The reversal of 28158005 is 50085182.

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

It is an interprime number because it is at equal distance from previous prime (28157993) and next prime (28158017).

It can be written as a sum of positive squares in 2 ways, for example, as 19989841 + 8168164 = 4471^2 + 2858^2 .

It is not a de Polignac number, because 28158005 - 2²⁰ = 27109429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 2815796 + ... + 2815805.

It is an arithmetic number, because the mean of its divisors is an integer number (8447403).

Almost surely, 2^28158005 is an apocalyptic number.

It is an amenable number.

28158005 is a deficient number, since it is larger than the sum of its proper divisors (5631607).

28158005 is an equidigital number, since it uses as much as digits as its factorization.

28158005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5631606.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 28158005 is about 5306.4116877604. The cubic root of 28158005 is about 304.2290121362.

The spelling of 28158005 in words is "twenty-eight million, one hundred fifty-eight thousand, five".