228521285521 has 3 divisors (see below), whose sum is σ = 228521763561. Its totient is φ = 228520807482.

The previous prime is 228521285519. The next prime is 228521285561. The reversal of 228521285521 is 125582125822.

The square root of 228521285521 is 478039.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 228521285521 - 2¹ = 228521285519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (228521285561) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 239020 + ... + 717058.

It is an arithmetic number, because the mean of its divisors is an integer number (76173921187).

Almost surely, 2^228521285521 is an apocalyptic number.

228521285521 is the 478039-th square number.

228521285521 is the 239020-th centered octagonal number.

It is an amenable number.

228521285521 is a deficient number, since it is larger than the sum of its proper divisors (478040).

228521285521 is an frugal number, since it uses more digits than its factorization.

228521285521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 956078 (or 478039 counting only the distinct ones).

The product of its digits is 256000, while the sum is 43.

The spelling of 228521285521 in words is "two hundred twenty-eight billion, five hundred twenty-one million, two hundred eighty-five thousand, five hundred twenty-one".