28727840 has 24 divisors (see below), whose sum is σ = 67869900. Its totient is φ = 11491072.

The previous prime is 28727837. The next prime is 28727843. The reversal of 28727840 is 4872782.

It is an interprime number because it is at equal distance from previous prime (28727837) and next prime (28727843).

It can be written as a sum of positive squares in 2 ways, for example, as 28601104 + 126736 = 5348^2 + 356^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28727794 and 28727803.

It is not an unprimeable number, because it can be changed into a prime (28727843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89615 + ... + 89934.

Almost surely, 2^28727840 is an apocalyptic number.

28727840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28727840 is an abundant number, since it is smaller than the sum of its proper divisors (39142060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28727840 is a wasteful number, since it uses less digits than its factorization.

28727840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179564 (or 179556 counting only the distinct ones).

The product of its (nonzero) digits is 50176, while the sum is 38.

The square root of 28727840 is about 5359.8358183810. The cubic root of 28727840 is about 306.2675547344.

The spelling of 28727840 in words is "twenty-eight million, seven hundred twenty-seven thousand, eight hundred forty".