28751440 has 40 divisors (see below), whose sum is σ = 68118408. Its totient is φ = 11281920.

The previous prime is 28751431. The next prime is 28751447. The reversal of 28751440 is 4415782.

28751440 = T₃₂₇ + T₃₂₈ + ... + T₅₉₁.

It can be written as a sum of positive squares in 4 ways, for example, as 4426816 + 24324624 = 2104^2 + 4932^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28751447) 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 7 ways as a sum of consecutive naturals, for example, 850 + ... + 7630.

Almost surely, 2^28751440 is an apocalyptic number.

28751440 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 28751440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34059204).

28751440 is an abundant number, since it is smaller than the sum of its proper divisors (39366968).

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

28751440 is a wasteful number, since it uses less digits than its factorization.

28751440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6847 (or 6841 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 31.

The square root of 28751440 is about 5362.0369263928. The cubic root of 28751440 is about 306.3513983270.

The spelling of 28751440 in words is "twenty-eight million, seven hundred fifty-one thousand, four hundred forty".