31331222981 has 2 divisors, whose sum is σ = 31331222982. Its totient is φ = 31331222980.

The previous prime is 31331222969. The next prime is 31331222987. The reversal of 31331222981 is 18922213313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28126644100 + 3204578881 = 167710^2 + 56609^2 .

It is an emirp because it is prime and its reverse (18922213313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31331222981 - 2⁶ = 31331222917 is a prime.

It is a super-2 number, since 2×31331222981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31331222987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15665611490 + 15665611491.

It is an arithmetic number, because the mean of its divisors is an integer number (15665611491).

Almost surely, 2^31331222981 is an apocalyptic number.

It is an amenable number.

31331222981 is a deficient number, since it is larger than the sum of its proper divisors (1).

31331222981 is an equidigital number, since it uses as much as digits as its factorization.

31331222981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 35.

The spelling of 31331222981 in words is "thirty-one billion, three hundred thirty-one million, two hundred twenty-two thousand, nine hundred eighty-one".