28743440 has 80 divisors (see below), whose sum is σ = 73923840. Its totient is φ = 10306560.

The previous prime is 28743401. The next prime is 28743467. The reversal of 28743440 is 4434782.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 28743397 and 28743406.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78137 + ... + 78503.

It is an arithmetic number, because the mean of its divisors is an integer number (924048).

Almost surely, 2^28743440 is an apocalyptic number.

28743440 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 28743440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36961920).

28743440 is an abundant number, since it is smaller than the sum of its proper divisors (45180400).

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

28743440 is a wasteful number, since it uses less digits than its factorization.

28743440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480 (or 474 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 32.

The square root of 28743440 is about 5361.2908893288. The cubic root of 28743440 is about 306.3229819123.

The spelling of 28743440 in words is "twenty-eight million, seven hundred forty-three thousand, four hundred forty".