28440720 has 480 divisors, whose sum is σ = 129991680. Its totient is φ = 5598720.

The previous prime is 28440689. The next prime is 28440721. The reversal of 28440720 is 2704482.

28440720 = 32³ + 33³ + ... + 103³.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28440721) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1496871 + ... + 1496889.

It is an arithmetic number, because the mean of its divisors is an integer number (270816).

Almost surely, 2^28440720 is an apocalyptic number.

28440720 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 28440720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64995840).

28440720 is an abundant number, since it is smaller than the sum of its proper divisors (101550960).

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

28440720 is a wasteful number, since it uses less digits than its factorization.

28440720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

The square root of 28440720 is about 5332.9841552362. The cubic root of 28440720 is about 305.2438075641.

It can be divided in two parts, 28440 and 720, that multiplied together give a triangular number (20476800 = T₆₃₉₉).

The spelling of 28440720 in words is "twenty-eight million, four hundred forty thousand, seven hundred twenty".