28393840 has 40 divisors (see below), whose sum is σ = 66714480. Its totient is φ = 11237376.

The previous prime is 28393831. The next prime is 28393843. The reversal of 28393840 is 4839382.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 28393840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28393843) 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, 5931 + ... + 9589.

It is an arithmetic number, because the mean of its divisors is an integer number (1667862).

Almost surely, 2^28393840 is an apocalyptic number.

28393840 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 28393840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33357240).

28393840 is an abundant number, since it is smaller than the sum of its proper divisors (38320640).

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

28393840 is a wasteful number, since it uses less digits than its factorization.

28393840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3769 (or 3763 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 28393840 is about 5328.5870547454. The cubic root of 28393840 is about 305.0760000520.

The spelling of 28393840 in words is "twenty-eight million, three hundred ninety-three thousand, eight hundred forty".