1191912091 has 2 divisors, whose sum is σ = 1191912092. Its totient is φ = 1191912090.

The previous prime is 1191912079. The next prime is 1191912097. The reversal of 1191912091 is 1902191911.

It is a strong prime.

It is an emirp because it is prime and its reverse (1902191911) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1191912091 - 2⁹ = 1191911579 is a prime.

It is not a weakly prime, because it can be changed into another prime (1191912097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 595956045 + 595956046.

It is an arithmetic number, because the mean of its divisors is an integer number (595956046).

Almost surely, 2^1191912091 is an apocalyptic number.

1191912091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1191912091 is an equidigital number, since it uses as much as digits as its factorization.

1191912091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1458, while the sum is 34.

The square root of 1191912091 is about 34524.0798718807. The cubic root of 1191912091 is about 1060.2657726242.

The spelling of 1191912091 in words is "one billion, one hundred ninety-one million, nine hundred twelve thousand, ninety-one".