31818181985 has 4 divisors (see below), whose sum is σ = 38181818388. Its totient is φ = 25454545584.

The previous prime is 31818181973. The next prime is 31818182017. The reversal of 31818181985 is 58918181813.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20538042721 + 11280139264 = 143311^2 + 106208^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31818181985 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 3181818194 + ... + 3181818203.

It is an arithmetic number, because the mean of its divisors is an integer number (9545454597).

Almost surely, 2^31818181985 is an apocalyptic number.

It is an amenable number.

31818181985 is a deficient number, since it is larger than the sum of its proper divisors (6363636403).

31818181985 is an equidigital number, since it uses as much as digits as its factorization.

31818181985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6363636402.

The product of its digits is 552960, while the sum is 53.

The spelling of 31818181985 in words is "thirty-one billion, eight hundred eighteen million, one hundred eighty-one thousand, nine hundred eighty-five".