1181921 has 4 divisors (see below), whose sum is σ = 1272852. Its totient is φ = 1090992.

The previous prime is 1181911. The next prime is 1181923. The reversal of 1181921 is 1291811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1291811 = 107 ⋅12073.

It can be written as a sum of positive squares in 2 ways, for example, as 483025 + 698896 = 695^2 + 836^2 .

It is a cyclic number.

It is not a de Polignac number, because 1181921 - 2¹⁰ = 1180897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1181923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45446 + ... + 45471.

It is an arithmetic number, because the mean of its divisors is an integer number (318213).

2^1181921 is an apocalyptic number.

It is an amenable number.

1181921 is a deficient number, since it is larger than the sum of its proper divisors (90931).

1181921 is an equidigital number, since it uses as much as digits as its factorization.

1181921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90930.

The product of its digits is 144, while the sum is 23.

The square root of 1181921 is about 1087.1619014664. The cubic root of 1181921 is about 105.7294930121.

The spelling of 1181921 in words is "one million, one hundred eighty-one thousand, nine hundred twenty-one".