31313220431 has 4 divisors (see below), whose sum is σ = 33155174592. Its totient is φ = 29471266272.

The previous prime is 31313220401. The next prime is 31313220443. The reversal of 31313220431 is 13402231313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13402231313 = 6571 ⋅2039603.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31313220431 is a prime.

It is a super-2 number, since 2×31313220431² (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 = 31313220397 and 31313220406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31313220401) 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, 920977055 + ... + 920977088.

It is an arithmetic number, because the mean of its divisors is an integer number (8288793648).

Almost surely, 2^31313220431 is an apocalyptic number.

31313220431 is a deficient number, since it is larger than the sum of its proper divisors (1841954161).

31313220431 is a wasteful number, since it uses less digits than its factorization.

31313220431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1841954160.

The product of its (nonzero) digits is 1296, while the sum is 23.

Adding to 31313220431 its reverse (13402231313), we get a palindrome (44715451744).

The spelling of 31313220431 in words is "thirty-one billion, three hundred thirteen million, two hundred twenty thousand, four hundred thirty-one".