1191216133 has 4 divisors (see below), whose sum is σ = 1191295840. Its totient is φ = 1191136428.

The previous prime is 1191216121. The next prime is 1191216149. The reversal of 1191216133 is 3316121911.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 3316121911 = 7643 ⋅433877.

It is a 3-Lehmer number, since φ(1191216133) divides (1191216133-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1191216133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1191216193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9963 + ... + 49816.

It is an arithmetic number, because the mean of its divisors is an integer number (297823960).

It is a Poulet number, since it divides 2^1191216132-1.

Almost surely, 2^1191216133 is an apocalyptic number.

1191216133 is the 19927-th octagonal number.

It is an amenable number.

1191216133 is a deficient number, since it is larger than the sum of its proper divisors (79707).

1191216133 is an equidigital number, since it uses as much as digits as its factorization.

1191216133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79706.

The product of its digits is 972, while the sum is 28.

The square root of 1191216133 is about 34513.9990873269. Note that the first 3 decimals coincide. The cubic root of 1191216133 is about 1060.0593692273.

The spelling of 1191216133 in words is "one billion, one hundred ninety-one million, two hundred sixteen thousand, one hundred thirty-three".