228208521 has 4 divisors (see below), whose sum is σ = 304278032. Its totient is φ = 152139012.

The previous prime is 228208517. The next prime is 228208559. The reversal of 228208521 is 125802822.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 228208521 - 2² = 228208517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (228208021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38034751 + ... + 38034756.

It is an arithmetic number, because the mean of its divisors is an integer number (76069508).

Almost surely, 2^228208521 is an apocalyptic number.

It is an amenable number.

228208521 is a deficient number, since it is larger than the sum of its proper divisors (76069511).

228208521 is an equidigital number, since it uses as much as digits as its factorization.

228208521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76069510.

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 228208521 is about 15106.5721128256. The cubic root of 228208521 is about 611.0976572600.

The spelling of 228208521 in words is "two hundred twenty-eight million, two hundred eight thousand, five hundred twenty-one".