12171321831 has 4 divisors (see below), whose sum is σ = 16228429112. Its totient is φ = 8114214552.

The previous prime is 12171321823. The next prime is 12171321847. The reversal of 12171321831 is 13812317121.

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

It is not a de Polignac number, because 12171321831 - 2³ = 12171321823 is a prime.

It is a super-2 number, since 2×12171321831² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12171321731) 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, 2028553636 + ... + 2028553641.

It is an arithmetic number, because the mean of its divisors is an integer number (4057107278).

Almost surely, 2^12171321831 is an apocalyptic number.

12171321831 is a deficient number, since it is larger than the sum of its proper divisors (4057107281).

12171321831 is an equidigital number, since it uses as much as digits as its factorization.

12171321831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4057107280.

The product of its digits is 2016, while the sum is 30.

Adding to 12171321831 its reverse (13812317121), we get a palindrome (25983638952).

The spelling of 12171321831 in words is "twelve billion, one hundred seventy-one million, three hundred twenty-one thousand, eight hundred thirty-one".