228116821 has 2 divisors, whose sum is σ = 228116822. Its totient is φ = 228116820.

The previous prime is 228116797. The next prime is 228116909. The reversal of 228116821 is 128611822.

228116821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 150430225 + 77686596 = 12265^2 + 8814^2 .

It is a cyclic number.

It is not a de Polignac number, because 228116821 - 2⁹ = 228116309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (228116221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 114058410 + 114058411.

It is an arithmetic number, because the mean of its divisors is an integer number (114058411).

Almost surely, 2^228116821 is an apocalyptic number.

It is an amenable number.

228116821 is a deficient number, since it is larger than the sum of its proper divisors (1).

228116821 is an equidigital number, since it uses as much as digits as its factorization.

228116821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3072, while the sum is 31.

The square root of 228116821 is about 15103.5367050238. The cubic root of 228116821 is about 611.0157947564.

The spelling of 228116821 in words is "two hundred twenty-eight million, one hundred sixteen thousand, eight hundred twenty-one".