1091287811 has 4 divisors (see below), whose sum is σ = 1092486624. Its totient is φ = 1090089000.

The previous prime is 1091287807. The next prime is 1091287853. The reversal of 1091287811 is 1187821901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1187821901 = 7 ⋅169688843.

It is a cyclic number.

It is not a de Polignac number, because 1091287811 - 2² = 1091287807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1091289811) 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 in 3 ways as a sum of consecutive naturals, for example, 598040 + ... + 599861.

It is an arithmetic number, because the mean of its divisors is an integer number (273121656).

Almost surely, 2^1091287811 is an apocalyptic number.

1091287811 is a deficient number, since it is larger than the sum of its proper divisors (1198813).

1091287811 is an equidigital number, since it uses as much as digits as its factorization.

1091287811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1198812.

The product of its (nonzero) digits is 8064, while the sum is 38.

The square root of 1091287811 is about 33034.6456163828. The cubic root of 1091287811 is about 1029.5476101121.

The spelling of 1091287811 in words is "one billion, ninety-one million, two hundred eighty-seven thousand, eight hundred eleven".