28101440 has 56 divisors (see below), whose sum is σ = 67510152. Its totient is φ = 11141120.

The previous prime is 28101433. The next prime is 28101449. The reversal of 28101440 is 4410182.

It can be written as a sum of positive squares in 4 ways, for example, as 8952064 + 19149376 = 2992^2 + 4376^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28101449) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 43520 + ... + 44160.

Almost surely, 2^28101440 is an apocalyptic number.

28101440 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 28101440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33755076).

28101440 is an abundant number, since it is smaller than the sum of its proper divisors (39408712).

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

28101440 is a wasteful number, since it uses less digits than its factorization.

28101440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795 (or 785 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 28101440 is about 5301.0791354214. The cubic root of 28101440 is about 304.0251595059.

The spelling of 28101440 in words is "twenty-eight million, one hundred one thousand, four hundred forty".