31311221331 has 12 divisors (see below), whose sum is σ = 45206734488. Its totient is φ = 19268443584.

The previous prime is 31311221329. The next prime is 31311221351. The reversal of 31311221331 is 13312211313.

It is a happy number.

It is not a de Polignac number, because 31311221331 - 2¹ = 31311221329 is a prime.

It is a super-2 number, since 2×31311221331² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31311221298 and 31311221307.

It is not an unprimeable number, because it can be changed into a prime (31311221351) 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 11 ways as a sum of consecutive naturals, for example, 30878410 + ... + 30879423.

It is an arithmetic number, because the mean of its divisors is an integer number (3767227874).

Almost surely, 2^31311221331 is an apocalyptic number.

31311221331 is a deficient number, since it is larger than the sum of its proper divisors (13895513157).

31311221331 is a wasteful number, since it uses less digits than its factorization.

31311221331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61757862 (or 61757849 counting only the distinct ones).

The product of its digits is 324, while the sum is 21.

Adding to 31311221331 its reverse (13312211313), we get a palindrome (44623432644).

The spelling of 31311221331 in words is "thirty-one billion, three hundred eleven million, two hundred twenty-one thousand, three hundred thirty-one".