28187723 has 4 divisors (see below), whose sum is σ = 28240368. Its totient is φ = 28135080.

The previous prime is 28187699. The next prime is 28187729. The reversal of 28187723 is 32778182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32778182 = 2 ⋅16389091.

It is a cyclic number.

It is not a de Polignac number, because 28187723 - 2¹² = 28183627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28187729) 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 in 3 ways as a sum of consecutive naturals, for example, 25511 + ... + 26592.

It is an arithmetic number, because the mean of its divisors is an integer number (7060092).

Almost surely, 2^28187723 is an apocalyptic number.

28187723 is a deficient number, since it is larger than the sum of its proper divisors (52645).

28187723 is an equidigital number, since it uses as much as digits as its factorization.

28187723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52644.

The product of its digits is 37632, while the sum is 38.

The square root of 28187723 is about 5309.2111466771. The cubic root of 28187723 is about 304.3360024218.

The spelling of 28187723 in words is "twenty-eight million, one hundred eighty-seven thousand, seven hundred twenty-three".