228507821 has 2 divisors, whose sum is σ = 228507822. Its totient is φ = 228507820.

The previous prime is 228507803. The next prime is 228507823. The reversal of 228507821 is 128705822.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 217710025 + 10797796 = 14755^2 + 3286^2 .

It is a cyclic number.

It is not a de Polignac number, because 228507821 - 2⁶ = 228507757 is a prime.

Together with 228507823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (228507823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 114253910 + 114253911.

It is an arithmetic number, because the mean of its divisors is an integer number (114253911).

Almost surely, 2^228507821 is an apocalyptic number.

It is an amenable number.

228507821 is a deficient number, since it is larger than the sum of its proper divisors (1).

228507821 is an equidigital number, since it uses as much as digits as its factorization.

228507821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 228507821 is about 15116.4751513043. The cubic root of 228507821 is about 611.3646961163.

The spelling of 228507821 in words is "two hundred twenty-eight million, five hundred seven thousand, eight hundred twenty-one".