31131242431 has 4 divisors (see below), whose sum is σ = 31131623952. Its totient is φ = 31130860912.

The previous prime is 31131242419. The next prime is 31131242479. The reversal of 31131242431 is 13424213113.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 13424213113 = 9419 ⋅1425227.

It is a cyclic number.

It is not a de Polignac number, because 31131242431 - 2²⁷ = 30997024703 is a prime.

It is a super-2 number, since 2×31131242431² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31131242396 and 31131242405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131242731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13390 + ... + 249883.

It is an arithmetic number, because the mean of its divisors is an integer number (7782905988).

Almost surely, 2^31131242431 is an apocalyptic number.

31131242431 is a deficient number, since it is larger than the sum of its proper divisors (381521).

31131242431 is a wasteful number, since it uses less digits than its factorization.

31131242431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381520.

The product of its digits is 1728, while the sum is 25.

Adding to 31131242431 its reverse (13424213113), we get a palindrome (44555455544).

The spelling of 31131242431 in words is "thirty-one billion, one hundred thirty-one million, two hundred forty-two thousand, four hundred thirty-one".