1123129991 has 2 divisors, whose sum is σ = 1123129992. Its totient is φ = 1123129990.

The previous prime is 1123129967. The next prime is 1123130053. The reversal of 1123129991 is 1999213211.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1123129991 - 2⁶ = 1123129927 is a prime.

It is a super-2 number, since 2×1123129991² = 2522841953367320162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1123129921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 561564995 + 561564996.

It is an arithmetic number, because the mean of its divisors is an integer number (561564996).

Almost surely, 2^1123129991 is an apocalyptic number.

1123129991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1123129991 is an equidigital number, since it uses as much as digits as its factorization.

1123129991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8748, while the sum is 38.

The square root of 1123129991 is about 33513.1316203067. The cubic root of 1123129991 is about 1039.4653289043.

The spelling of 1123129991 in words is "one billion, one hundred twenty-three million, one hundred twenty-nine thousand, nine hundred ninety-one".