28993440 has 96 divisors (see below), whose sum is σ = 104388480. Its totient is φ = 6626304.

The previous prime is 28993439. The next prime is 28993453. The reversal of 28993440 is 4439982.

It is a tau number, because it is divible by the number of its divisors (96).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 955 + ... + 7674.

It is an arithmetic number, because the mean of its divisors is an integer number (1087380).

Almost surely, 2^28993440 is an apocalyptic number.

28993440 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 28993440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52194240).

28993440 is an abundant number, since it is smaller than the sum of its proper divisors (75395040).

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

28993440 is a wasteful number, since it uses less digits than its factorization.

28993440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8654 (or 8646 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 28993440 is about 5384.5556919768. Note that the first 3 decimals coincide. The cubic root of 28993440 is about 307.2085148465.

The spelling of 28993440 in words is "twenty-eight million, nine hundred ninety-three thousand, four hundred forty".