1181335681 has 4 divisors (see below), whose sum is σ = 1181675092. Its totient is φ = 1180996272.

The previous prime is 1181335679. The next prime is 1181335691. The reversal of 1181335681 is 1865331811.

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

It can be written as a sum of positive squares in 2 ways, for example, as 922640625 + 258695056 = 30375^2 + 16084^2 .

It is a cyclic number.

It is not a de Polignac number, because 1181335681 - 2¹ = 1181335679 is a prime.

It is a super-2 number, since 2×1181335681² = 2791107982407467522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1181335681.

It is not an unprimeable number, because it can be changed into a prime (1181335651) 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, 164430 + ... + 171463.

It is an arithmetic number, because the mean of its divisors is an integer number (295418773).

Almost surely, 2^1181335681 is an apocalyptic number.

It is an amenable number.

1181335681 is a deficient number, since it is larger than the sum of its proper divisors (339411).

1181335681 is an equidigital number, since it uses as much as digits as its factorization.

1181335681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339410.

The product of its digits is 17280, while the sum is 37.

The square root of 1181335681 is about 34370.5641647035. The cubic root of 1181335681 is about 1057.1203676935.

The spelling of 1181335681 in words is "one billion, one hundred eighty-one million, three hundred thirty-five thousand, six hundred eighty-one".