31100099981 has 2 divisors, whose sum is σ = 31100099982. Its totient is φ = 31100099980.

The previous prime is 31100099969. The next prime is 31100099983. The reversal of 31100099981 is 18999000113.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25196482756 + 5903617225 = 158734^2 + 76835^2 .

It is a cyclic number.

It is not a de Polignac number, because 31100099981 - 2²⁶ = 31032991117 is a prime.

It is a super-2 number, since 2×31100099981² (a number of 22 digits) contains 22 as substring.

Together with 31100099983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31100099983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15550049990 + 15550049991.

It is an arithmetic number, because the mean of its divisors is an integer number (15550049991).

Almost surely, 2^31100099981 is an apocalyptic number.

It is an amenable number.

31100099981 is a deficient number, since it is larger than the sum of its proper divisors (1).

31100099981 is an equidigital number, since it uses as much as digits as its factorization.

31100099981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 41.

The spelling of 31100099981 in words is "thirty-one billion, one hundred million, ninety-nine thousand, nine hundred eighty-one".