28775240 has 32 divisors (see below), whose sum is σ = 69725880. Its totient is φ = 10624512.

The previous prime is 28775239. The next prime is 28775261. The reversal of 28775240 is 4257782.

It can be written as a sum of positive squares in 4 ways, for example, as 16144324 + 12630916 = 4018^2 + 3554^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28775240.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27149 + ... + 28188.

Almost surely, 2^28775240 is an apocalyptic number.

28775240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28775240 is an abundant number, since it is smaller than the sum of its proper divisors (40950640).

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

28775240 is a wasteful number, since it uses less digits than its factorization.

28775240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55361 (or 55357 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 35.

The square root of 28775240 is about 5364.2557731711. The cubic root of 28775240 is about 306.4359060058.

The spelling of 28775240 in words is "twenty-eight million, seven hundred seventy-five thousand, two hundred forty".