1091920091 has 2 divisors, whose sum is σ = 1091920092. Its totient is φ = 1091920090.

The previous prime is 1091920087. The next prime is 1091920097. The reversal of 1091920091 is 1900291901.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1091920091 - 2² = 1091920087 is a prime.

It is not a weakly prime, because it can be changed into another prime (1091920097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545960045 + 545960046.

It is an arithmetic number, because the mean of its divisors is an integer number (545960046).

Almost surely, 2^1091920091 is an apocalyptic number.

1091920091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091920091 is an equidigital number, since it uses as much as digits as its factorization.

1091920091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 32.

The square root of 1091920091 is about 33044.2141834240. The cubic root of 1091920091 is about 1029.7464078617.

The spelling of 1091920091 in words is "one billion, ninety-one million, nine hundred twenty thousand, ninety-one".