11191681 has 2 divisors, whose sum is σ = 11191682. Its totient is φ = 11191680.

The previous prime is 11191669. The next prime is 11191699. The reversal of 11191681 is 18619111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7750656 + 3441025 = 2784^2 + 1855^2 .

It is a cyclic number.

It is not a de Polignac number, because 11191681 - 2⁷ = 11191553 is a prime.

It is a super-2 number, since 2×11191681² = 250507447211522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (11191381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5595840 + 5595841.

It is an arithmetic number, because the mean of its divisors is an integer number (5595841).

Almost surely, 2^11191681 is an apocalyptic number.

It is an amenable number.

11191681 is a deficient number, since it is larger than the sum of its proper divisors (1).

11191681 is an equidigital number, since it uses as much as digits as its factorization.

11191681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 28.

The square root of 11191681 is about 3345.3969869060. The cubic root of 11191681 is about 223.6823796162.

The spelling of 11191681 in words is "eleven million, one hundred ninety-one thousand, six hundred eighty-one".