1181391663 has 8 divisors (see below), whose sum is σ = 1578398976. Its totient is φ = 785989400.

The previous prime is 1181391623. The next prime is 1181391683. The reversal of 1181391663 is 3661931811.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1181391663 - 2²⁴ = 1164614447 is a prime.

It is a super-2 number, since 2×1181391663² = 2791372522811811138, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1181391613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 399543 + ... + 402488.

It is an arithmetic number, because the mean of its divisors is an integer number (197299872).

Almost surely, 2^1181391663 is an apocalyptic number.

1181391663 is a deficient number, since it is larger than the sum of its proper divisors (397007313).

1181391663 is an equidigital number, since it uses as much as digits as its factorization.

1181391663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 802525.

The product of its digits is 23328, while the sum is 39.

The square root of 1181391663 is about 34371.3785437826. The cubic root of 1181391663 is about 1057.1370659610.

The spelling of 1181391663 in words is "one billion, one hundred eighty-one million, three hundred ninety-one thousand, six hundred sixty-three".