28555520 has 72 divisors (see below), whose sum is σ = 78195264. Its totient is φ = 9787392.

The previous prime is 28555519. The next prime is 28555523. The reversal of 28555520 is 2555582.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (28555523) 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, 7367 + ... + 10553.

Almost surely, 2^28555520 is an apocalyptic number.

28555520 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 28555520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39097632).

28555520 is an abundant number, since it is smaller than the sum of its proper divisors (49639744).

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

28555520 is an equidigital number, since it uses as much as digits as its factorization.

28555520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3215 (or 3201 counting only the distinct ones).

The product of its (nonzero) digits is 20000, while the sum is 32.

The square root of 28555520 is about 5343.7365204508. The cubic root of 28555520 is about 305.6539582912.

The spelling of 28555520 in words is "twenty-eight million, five hundred fifty-five thousand, five hundred twenty".