12211997081 has 4 divisors (see below), whose sum is σ = 12248891664. Its totient is φ = 12175102500.

The previous prime is 12211997027. The next prime is 12211997111. The reversal of 12211997081 is 18079911221.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12211997081 is a prime.

It is a super-2 number, since 2×12211997081² (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 (12211997011) 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, 18446795 + ... + 18447456.

It is an arithmetic number, because the mean of its divisors is an integer number (3062222916).

Almost surely, 2^12211997081 is an apocalyptic number.

It is an amenable number.

12211997081 is a deficient number, since it is larger than the sum of its proper divisors (36894583).

12211997081 is an equidigital number, since it uses as much as digits as its factorization.

12211997081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36894582.

The product of its (nonzero) digits is 18144, while the sum is 41.

The spelling of 12211997081 in words is "twelve billion, two hundred eleven million, nine hundred ninety-seven thousand, eighty-one".