228310991 has 2 divisors, whose sum is σ = 228310992. Its totient is φ = 228310990.

The previous prime is 228310987. The next prime is 228310993. The reversal of 228310991 is 199013822.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 228310991 - 2² = 228310987 is a prime.

It is a super-2 number, since 2×228310991² = 104251817222804162, which contains 22 as substring.

Together with 228310993, 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 (228310993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 114155495 + 114155496.

It is an arithmetic number, because the mean of its divisors is an integer number (114155496).

Almost surely, 2^228310991 is an apocalyptic number.

228310991 is a deficient number, since it is larger than the sum of its proper divisors (1).

228310991 is an equidigital number, since it uses as much as digits as its factorization.

228310991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 228310991 is about 15109.9633024041. The cubic root of 228310991 is about 611.1891084272.

The spelling of 228310991 in words is "two hundred twenty-eight million, three hundred ten thousand, nine hundred ninety-one".