28188523 has 6 divisors (see below), whose sum is σ = 30984212. Its totient is φ = 25625820.

The previous prime is 28188509. The next prime is 28188541. The reversal of 28188523 is 32588182.

It is a de Polignac number, because none of the positive numbers 2^k-28188523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28188553) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 116361 + ... + 116602.

Almost surely, 2^28188523 is an apocalyptic number.

28188523 is a deficient number, since it is larger than the sum of its proper divisors (2795689).

28188523 is a wasteful number, since it uses less digits than its factorization.

28188523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232985 (or 232974 counting only the distinct ones).

The product of its digits is 30720, while the sum is 37.

The square root of 28188523 is about 5309.2864869020. The cubic root of 28188523 is about 304.3388815298.

It can be divided in two parts, 281 and 88523, that added together give a square (88804 = 298²).

The spelling of 28188523 in words is "twenty-eight million, one hundred eighty-eight thousand, five hundred twenty-three".