28378440 has 96 divisors (see below), whose sum is σ = 97676280. Its totient is φ = 7120896.

The previous prime is 28378421. The next prime is 28378507. The reversal of 28378440 is 4487382.

28378440 = T₃₁₄ + T₃₁₅ + ... + T₅₈₅.

It can be written as a sum of positive squares in 4 ways, for example, as 23097636 + 5280804 = 4806^2 + 2298^2 .

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 = 28378395 and 28378404.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3802 + ... + 8438.

Almost surely, 2^28378440 is an apocalyptic number.

28378440 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 28378440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48838140).

28378440 is an abundant number, since it is smaller than the sum of its proper divisors (69297840).

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

28378440 is a wasteful number, since it uses less digits than its factorization.

28378440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4671 (or 4664 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 36.

The square root of 28378440 is about 5327.1418227789. The cubic root of 28378440 is about 305.0208352693.

The spelling of 28378440 in words is "twenty-eight million, three hundred seventy-eight thousand, four hundred forty".