999991229 has 2 divisors, whose sum is σ = 999991230. Its totient is φ = 999991228.

The previous prime is 999991207. The next prime is 999991231. The reversal of 999991229 is 922199999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 587820025 + 412171204 = 24245^2 + 20302^2 .

It is a cyclic number.

It is not a de Polignac number, because 999991229 - 2⁸ = 999990973 is a prime.

Together with 999991231, 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 (999991829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499995614 + 499995615.

It is an arithmetic number, because the mean of its divisors is an integer number (499995615).

Almost surely, 2^999991229 is an apocalyptic number.

It is an amenable number.

999991229 is a deficient number, since it is larger than the sum of its proper divisors (1).

999991229 is an equidigital number, since it uses as much as digits as its factorization.

999991229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2125764, while the sum is 59.

The square root of 999991229 is about 31622.6379196929. The cubic root of 999991229 is about 999.9970763248.

The spelling of 999991229 in words is "nine hundred ninety-nine million, nine hundred ninety-one thousand, two hundred twenty-nine".