228784921 has 2 divisors, whose sum is σ = 228784922. Its totient is φ = 228784920.

The previous prime is 228784877. The next prime is 228784999. The reversal of 228784921 is 129487822.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 201952521 + 26832400 = 14211^2 + 5180^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-228784921 is a prime.

It is equal to p_12579469 and since 228784921 and 12579469 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (228784021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 114392460 + 114392461.

It is an arithmetic number, because the mean of its divisors is an integer number (114392461).

Almost surely, 2^228784921 is an apocalyptic number.

It is an amenable number.

228784921 is a deficient number, since it is larger than the sum of its proper divisors (1).

228784921 is an equidigital number, since it uses as much as digits as its factorization.

228784921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129024, while the sum is 43.

The square root of 228784921 is about 15125.6378708470. The cubic root of 228784921 is about 611.6117200834.

The spelling of 228784921 in words is "two hundred twenty-eight million, seven hundred eighty-four thousand, nine hundred twenty-one".