28423840 has 48 divisors (see below), whose sum is σ = 68312160. Its totient is φ = 11173120.

The previous prime is 28423831. The next prime is 28423849. The reversal of 28423840 is 4832482.

It is an interprime number because it is at equal distance from previous prime (28423831) and next prime (28423849).

It is not an unprimeable number, because it can be changed into a prime (28423849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7935 + ... + 10945.

It is an arithmetic number, because the mean of its divisors is an integer number (1423170).

Almost surely, 2^28423840 is an apocalyptic number.

28423840 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 28423840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34156080).

28423840 is an abundant number, since it is smaller than the sum of its proper divisors (39888320).

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

28423840 is a wasteful number, since it uses less digits than its factorization.

28423840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3085 (or 3077 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 31.

The square root of 28423840 is about 5331.4013167272. The cubic root of 28423840 is about 305.1834066651.

The spelling of 28423840 in words is "twenty-eight million, four hundred twenty-three thousand, eight hundred forty".