28217520 has 60 divisors (see below), whose sum is σ = 94766256. Its totient is φ = 7524480.

The previous prime is 28217513. The next prime is 28217537. The reversal of 28217520 is 2571282.

It is a tau number, because it is divible by the number of its divisors (60).

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 11 ways as a sum of consecutive naturals, for example, 18876 + ... + 20315.

Almost surely, 2^28217520 is an apocalyptic number.

28217520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28217520 is an abundant number, since it is smaller than the sum of its proper divisors (66548736).

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

28217520 is a wasteful number, since it uses less digits than its factorization.

28217520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39210 (or 39201 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 28217520 is about 5312.0165662392. The cubic root of 28217520 is about 304.4432016493.

The spelling of 28217520 in words is "twenty-eight million, two hundred seventeen thousand, five hundred twenty".