133311991 has 2 divisors, whose sum is σ = 133311992. Its totient is φ = 133311990.

The previous prime is 133311989. The next prime is 133312051. The reversal of 133311991 is 199113331.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 133311991 - 2¹ = 133311989 is a prime.

Together with 133311989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133311931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66655995 + 66655996.

It is an arithmetic number, because the mean of its divisors is an integer number (66655996).

Almost surely, 2^133311991 is an apocalyptic number.

133311991 is a deficient number, since it is larger than the sum of its proper divisors (1).

133311991 is an equidigital number, since it uses as much as digits as its factorization.

133311991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2187, while the sum is 31.

The square root of 133311991 is about 11546.0811966658. The cubic root of 133311991 is about 510.8456954223.

The spelling of 133311991 in words is "one hundred thirty-three million, three hundred eleven thousand, nine hundred ninety-one".