1091172091 has 4 divisors (see below), whose sum is σ = 1106540784. Its totient is φ = 1075803400.

The previous prime is 1091172083. The next prime is 1091172097. The reversal of 1091172091 is 1902711901.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1091172091 - 2³ = 1091172083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1091172097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7684240 + ... + 7684381.

It is an arithmetic number, because the mean of its divisors is an integer number (276635196).

Almost surely, 2^1091172091 is an apocalyptic number.

1091172091 is a deficient number, since it is larger than the sum of its proper divisors (15368693).

1091172091 is an equidigital number, since it uses as much as digits as its factorization.

1091172091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15368692.

The product of its (nonzero) digits is 1134, while the sum is 31.

The square root of 1091172091 is about 33032.8940754515. The cubic root of 1091172091 is about 1029.5112177996.

Adding to 1091172091 its reverse (1902711901), we get a palindrome (2993883992).

The spelling of 1091172091 in words is "one billion, ninety-one million, one hundred seventy-two thousand, ninety-one".