28158840 has 96 divisors (see below), whose sum is σ = 94938480. Its totient is φ = 7506432.

The previous prime is 28158811. The next prime is 28158853. The reversal of 28158840 is 4885182.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28158795 and 28158804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8272 + ... + 11168.

Almost surely, 2^28158840 is an apocalyptic number.

28158840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28158840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47469240).

28158840 is an abundant number, since it is smaller than the sum of its proper divisors (66779640).

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

28158840 is a wasteful number, since it uses less digits than its factorization.

28158840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2923 (or 2907 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 28158840 is about 5306.4903655806. The cubic root of 28158840 is about 304.2320193179.

The spelling of 28158840 in words is "twenty-eight million, one hundred fifty-eight thousand, eight hundred forty".