28693440 has 224 divisors, whose sum is σ = 104973120. Its totient is φ = 7464960.

The previous prime is 28693429. The next prime is 28693447. The reversal of 28693440 is 4439682.

It is a happy number.

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 = 28693395 and 28693404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28693447) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 699820 + ... + 699860.

It is an arithmetic number, because the mean of its divisors is an integer number (468630).

Almost surely, 2^28693440 is an apocalyptic number.

28693440 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 28693440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52486560).

28693440 is an abundant number, since it is smaller than the sum of its proper divisors (76279680).

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

28693440 is an frugal number, since it uses more digits than its factorization.

28693440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 28693440 is about 5356.6258036193. The cubic root of 28693440 is about 306.1452597533.

The spelling of 28693440 in words is "twenty-eight million, six hundred ninety-three thousand, four hundred forty".