31323199981 has 2 divisors, whose sum is σ = 31323199982. Its totient is φ = 31323199980.

The previous prime is 31323199951. The next prime is 31323200011. The reversal of 31323199981 is 18999132313.

It is a balanced prime because it is at equal distance from previous prime (31323199951) and next prime (31323200011).

It can be written as a sum of positive squares in only one way, i.e., 30093575625 + 1229624356 = 173475^2 + 35066^2 .

It is a cyclic number.

It is not a de Polignac number, because 31323199981 - 2⁹ = 31323199469 is a prime.

It is a super-2 number, since 2×31323199981² (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 (31323199931) 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 as a sum of consecutive naturals, namely, 15661599990 + 15661599991.

It is an arithmetic number, because the mean of its divisors is an integer number (15661599991).

Almost surely, 2^31323199981 is an apocalyptic number.

It is an amenable number.

31323199981 is a deficient number, since it is larger than the sum of its proper divisors (1).

31323199981 is an equidigital number, since it uses as much as digits as its factorization.

31323199981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 314928, while the sum is 49.

The spelling of 31323199981 in words is "thirty-one billion, three hundred twenty-three million, one hundred ninety-nine thousand, nine hundred eighty-one".