228817521 has 8 divisors (see below), whose sum is σ = 338988960. Its totient is φ = 152544996.

The previous prime is 228817447. The next prime is 228817543. The reversal of 228817521 is 125718822.

It is not a de Polignac number, because 228817521 - 2²⁷ = 94599793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (228817571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4237335 + ... + 4237388.

It is an arithmetic number, because the mean of its divisors is an integer number (42373620).

Almost surely, 2^228817521 is an apocalyptic number.

It is an amenable number.

228817521 is a deficient number, since it is larger than the sum of its proper divisors (110171439).

228817521 is an equidigital number, since it uses as much as digits as its factorization.

228817521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8474732 (or 8474726 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 228817521 is about 15126.7154729637. The cubic root of 228817521 is about 611.6407686108.

The spelling of 228817521 in words is "two hundred twenty-eight million, eight hundred seventeen thousand, five hundred twenty-one".