28405280 has 24 divisors (see below), whose sum is σ = 67107852. Its totient is φ = 11362048.

The previous prime is 28405277. The next prime is 28405303. The reversal of 28405280 is 8250482.

It can be written as a sum of positive squares in 2 ways, for example, as 27331984 + 1073296 = 5228^2 + 1036^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88607 + ... + 88926.

Almost surely, 2^28405280 is an apocalyptic number.

28405280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28405280 is an abundant number, since it is smaller than the sum of its proper divisors (38702572).

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

28405280 is a wasteful number, since it uses less digits than its factorization.

28405280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177548 (or 177540 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 29.

The square root of 28405280 is about 5329.6604019393. The cubic root of 28405280 is about 305.1169666939.

The spelling of 28405280 in words is "twenty-eight million, four hundred five thousand, two hundred eighty".