28444640 has 96 divisors (see below), whose sum is σ = 77837760. Its totient is φ = 9621504.

The previous prime is 28444597. The next prime is 28444657. The reversal of 28444640 is 4644482.

It is a hoax number, since the sum of its digits (32) 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 (32).

It is a junction number, because it is equal to n+sod(n) for n = 28444597 and 28444606.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 121964 + ... + 122196.

It is an arithmetic number, because the mean of its divisors is an integer number (810810).

Almost surely, 2^28444640 is an apocalyptic number.

28444640 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 28444640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38918880).

28444640 is an abundant number, since it is smaller than the sum of its proper divisors (49393120).

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

28444640 is a wasteful number, since it uses less digits than its factorization.

28444640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364 (or 356 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 32.

The square root of 28444640 is about 5333.3516666352. The cubic root of 28444640 is about 305.2578308935.

The spelling of 28444640 in words is "twenty-eight million, four hundred forty-four thousand, six hundred forty".