1091096891 has 2 divisors, whose sum is σ = 1091096892. Its totient is φ = 1091096890.

The previous prime is 1091096861. The next prime is 1091096917. The reversal of 1091096891 is 1986901901.

It is a strong prime.

It is an emirp because it is prime and its reverse (1986901901) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1689601601 and 1061069861.

It is a cyclic number.

It is not a de Polignac number, because 1091096891 - 2¹⁸ = 1090834747 is a prime.

It is not a weakly prime, because it can be changed into another prime (1091096861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545548445 + 545548446.

It is an arithmetic number, because the mean of its divisors is an integer number (545548446).

Almost surely, 2^1091096891 is an apocalyptic number.

1091096891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091096891 is an equidigital number, since it uses as much as digits as its factorization.

1091096891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 44.

The square root of 1091096891 is about 33031.7557965059. The cubic root of 1091096891 is about 1029.4875670780.

The spelling of 1091096891 in words is "one billion, ninety-one million, ninety-six thousand, eight hundred ninety-one".