1191881 has 4 divisors (see below), whose sum is σ = 1224132. Its totient is φ = 1159632.

The previous prime is 1191847. The next prime is 1191899. The reversal of 1191881 is 1881911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1881911 = 61 ⋅30851.

It can be written as a sum of positive squares in 2 ways, for example, as 1092025 + 99856 = 1045^2 + 316^2 .

It is a cyclic number.

It is not a de Polignac number, because 1191881 - 2¹⁴ = 1175497 is a prime.

It is a super-2 number, since 2×1191881² = 2841160636322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1191821) 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 3 ways as a sum of consecutive naturals, for example, 16070 + ... + 16143.

It is an arithmetic number, because the mean of its divisors is an integer number (306033).

2^1191881 is an apocalyptic number.

It is an amenable number.

1191881 is a deficient number, since it is larger than the sum of its proper divisors (32251).

1191881 is an equidigital number, since it uses as much as digits as its factorization.

1191881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32250.

The product of its digits is 576, while the sum is 29.

The square root of 1191881 is about 1091.7330259729. The cubic root of 1191881 is about 106.0256553541.

The spelling of 1191881 in words is "one million, one hundred ninety-one thousand, eight hundred eighty-one".