1191228691 has 2 divisors, whose sum is σ = 1191228692. Its totient is φ = 1191228690.

The previous prime is 1191228683. The next prime is 1191228697. The reversal of 1191228691 is 1968221911.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1191228691 - 2³ = 1191228683 is a prime.

It is not a weakly prime, because it can be changed into another prime (1191228697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 595614345 + 595614346.

It is an arithmetic number, because the mean of its divisors is an integer number (595614346).

Almost surely, 2^1191228691 is an apocalyptic number.

1191228691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1191228691 is an equidigital number, since it uses as much as digits as its factorization.

1191228691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 40.

The square root of 1191228691 is about 34514.1810130271. The cubic root of 1191228691 is about 1060.0630943220.

The spelling of 1191228691 in words is "one billion, one hundred ninety-one million, two hundred twenty-eight thousand, six hundred ninety-one".