11981063681 has 4 divisors (see below), whose sum is σ = 12611646000. Its totient is φ = 11350481364.

The previous prime is 11981063663. The next prime is 11981063707. The reversal of 11981063681 is 18636018911.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18636018911 = 12983 ⋅1435417.

It is a de Polignac number, because none of the positive numbers 2^k-11981063681 is a prime.

It is a super-2 number, since 2×11981063681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11981063621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 315291131 + ... + 315291168.

It is an arithmetic number, because the mean of its divisors is an integer number (3152911500).

Almost surely, 2^11981063681 is an apocalyptic number.

It is an amenable number.

11981063681 is a deficient number, since it is larger than the sum of its proper divisors (630582319).

11981063681 is an equidigital number, since it uses as much as digits as its factorization.

11981063681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630582318.

The product of its (nonzero) digits is 62208, while the sum is 44.

The spelling of 11981063681 in words is "eleven billion, nine hundred eighty-one million, sixty-three thousand, six hundred eighty-one".