28028623 has 4 divisors (see below), whose sum is σ = 32032720. Its totient is φ = 24024528.

The previous prime is 28028593. The next prime is 28028641. The reversal of 28028623 is 32682082.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28028623 is a prime.

It is a super-2 number, since 2×28028623² = 1571207414552258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28028653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2002038 + ... + 2002051.

It is an arithmetic number, because the mean of its divisors is an integer number (8008180).

Almost surely, 2^28028623 is an apocalyptic number.

28028623 is a deficient number, since it is larger than the sum of its proper divisors (4004097).

28028623 is an equidigital number, since it uses as much as digits as its factorization.

28028623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4004096.

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 28028623 is about 5294.2065505607. The cubic root of 28028623 is about 303.7623337188.

The spelling of 28028623 in words is "twenty-eight million, twenty-eight thousand, six hundred twenty-three".