1091099911 has 4 divisors (see below), whose sum is σ = 1190290824. Its totient is φ = 991909000.

The previous prime is 1091099903. The next prime is 1091099939. The reversal of 1091099911 is 1199901901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1199901901 = 11 ⋅109081991.

It is a cyclic number.

It is not a de Polignac number, because 1091099911 - 2³ = 1091099903 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091099981) 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, 49595440 + ... + 49595461.

It is an arithmetic number, because the mean of its divisors is an integer number (297572706).

Almost surely, 2^1091099911 is an apocalyptic number.

1091099911 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1091099911 is a deficient number, since it is larger than the sum of its proper divisors (99190913).

1091099911 is an equidigital number, since it uses as much as digits as its factorization.

1091099911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99190912.

The product of its (nonzero) digits is 6561, while the sum is 40.

The square root of 1091099911 is about 33031.8015100600. The cubic root of 1091099911 is about 1029.4885169019.

The spelling of 1091099911 in words is "one billion, ninety-one million, ninety-nine thousand, nine hundred eleven".