11891009 has 12 divisors (see below), whose sum is σ = 13070592. Its totient is φ = 10810800.

The previous prime is 11891003. The next prime is 11891021. The reversal of 11891009 is 90019811.

It is not a de Polignac number, because 11891009 - 2⁴ = 11890993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11891003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11504 + ... + 12494.

It is an arithmetic number, because the mean of its divisors is an integer number (1089216).

Almost surely, 2^11891009 is an apocalyptic number.

It is an amenable number.

11891009 is a deficient number, since it is larger than the sum of its proper divisors (1179583).

11891009 is an equidigital number, since it uses as much as digits as its factorization.

11891009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1088 (or 1075 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 11891009 is about 3448.3342355404. The cubic root of 11891009 is about 228.2476085512.

The spelling of 11891009 in words is "eleven million, eight hundred ninety-one thousand, nine".