28005504 has 32 divisors (see below), whose sum is σ = 74390640. Its totient is φ = 9335040.

The previous prime is 28005491. The next prime is 28005521. The reversal of 28005504 is 40550082.

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36082 + ... + 36849.

Almost surely, 2^28005504 is an apocalyptic number.

28005504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28005504 is an abundant number, since it is smaller than the sum of its proper divisors (46385136).

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

28005504 is an equidigital number, since it uses as much as digits as its factorization.

28005504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72948 (or 72936 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 28005504 is about 5292.0226756884. The cubic root of 28005504 is about 303.6787927717.

Adding to 28005504 its reverse (40550082), we get a palindrome (68555586).

The spelling of 28005504 in words is "twenty-eight million, five thousand, five hundred four".