228717521 has 2 divisors, whose sum is σ = 228717522. Its totient is φ = 228717520.

The previous prime is 228717509. The next prime is 228717583. The reversal of 228717521 is 125717822.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 174900625 + 53816896 = 13225^2 + 7336^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-228717521 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221717521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 114358760 + 114358761.

It is an arithmetic number, because the mean of its divisors is an integer number (114358761).

Almost surely, 2^228717521 is an apocalyptic number.

It is an amenable number.

228717521 is a deficient number, since it is larger than the sum of its proper divisors (1).

228717521 is an equidigital number, since it uses as much as digits as its factorization.

228717521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15680, while the sum is 35.

The square root of 228717521 is about 15123.4097015190. The cubic root of 228717521 is about 611.5516539473.

The spelling of 228717521 in words is "two hundred twenty-eight million, seven hundred seventeen thousand, five hundred twenty-one".