31223321431 has 4 divisors (see below), whose sum is σ = 31227848872. Its totient is φ = 31218793992.

The previous prime is 31223321407. The next prime is 31223321477. The reversal of 31223321431 is 13412332213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13412332213 = 7 ⋅1916047459.

It is a cyclic number.

It is not a de Polignac number, because 31223321431 - 2²⁹ = 30686450519 is a prime.

It is a super-2 number, since 2×31223321431² (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 = 31223321396 and 31223321405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31223327431) 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 3 ways as a sum of consecutive naturals, for example, 2253360 + ... + 2267173.

It is an arithmetic number, because the mean of its divisors is an integer number (7806962218).

Almost surely, 2^31223321431 is an apocalyptic number.

31223321431 is a deficient number, since it is larger than the sum of its proper divisors (4527441).

31223321431 is an equidigital number, since it uses as much as digits as its factorization.

31223321431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4527440.

The product of its digits is 2592, while the sum is 25.

Adding to 31223321431 its reverse (13412332213), we get a palindrome (44635653644).

The spelling of 31223321431 in words is "thirty-one billion, two hundred twenty-three million, three hundred twenty-one thousand, four hundred thirty-one".