28775440 has 80 divisors (see below), whose sum is σ = 70995456. Its totient is φ = 10828800.

The previous prime is 28775429. The next prime is 28775459. The reversal of 28775440 is 4457782.

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

It is a self number, because there is not a number n which added to its sum of digits gives 28775440.

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, 101539 + ... + 101821.

Almost surely, 2^28775440 is an apocalyptic number.

28775440 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 28775440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35497728).

28775440 is an abundant number, since it is smaller than the sum of its proper divisors (42220016).

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

28775440 is a wasteful number, since it uses less digits than its factorization.

28775440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368 (or 362 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 37.

The square root of 28775440 is about 5364.2744150537. The cubic root of 28775440 is about 306.4366159569.

The spelling of 28775440 in words is "twenty-eight million, seven hundred seventy-five thousand, four hundred forty".