28505090 has 16 divisors (see below), whose sum is σ = 54327672. Its totient is φ = 10731264.

The previous prime is 28505053. The next prime is 28505093. The reversal of 28505090 is 9050582.

It can be written as a sum of positive squares in 4 ways, for example, as 22250089 + 6255001 = 4717^2 + 2501^2 .

It is not an unprimeable number, because it can be changed into a prime (28505093) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 83669 + ... + 84008.

Almost surely, 2^28505090 is an apocalyptic number.

28505090 is a deficient number, since it is larger than the sum of its proper divisors (25822582).

28505090 is a wasteful number, since it uses less digits than its factorization.

28505090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167701.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 28505090 is about 5339.0158269104. The cubic root of 28505090 is about 305.4739205730.

The spelling of 28505090 in words is "twenty-eight million, five hundred five thousand, ninety".