991311227 has 2 divisors, whose sum is σ = 991311228. Its totient is φ = 991311226.

The previous prime is 991311199. The next prime is 991311239. The reversal of 991311227 is 722113199.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991311227 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991311287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495655613 + 495655614.

It is an arithmetic number, because the mean of its divisors is an integer number (495655614).

Almost surely, 2^991311227 is an apocalyptic number.

991311227 is a deficient number, since it is larger than the sum of its proper divisors (1).

991311227 is an equidigital number, since it uses as much as digits as its factorization.

991311227 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6804, while the sum is 35.

The square root of 991311227 is about 31485.0953150852. The cubic root of 991311227 is about 997.0953132976.

The spelling of 991311227 in words is "nine hundred ninety-one million, three hundred eleven thousand, two hundred twenty-seven".