31531718185081 has 16 divisors (see below), whose sum is σ = 31913179562880. Its totient is φ = 31152866008320.

The previous prime is 31531718185067. The next prime is 31531718185087. The reversal of 31531718185081 is 18058181713513.

It is a cyclic number.

It is not a de Polignac number, because 31531718185081 - 2⁹ = 31531718184569 is a prime.

It is a super-2 number, since 2×31531718185081² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31531718185087) 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 in 15 ways as a sum of consecutive naturals, for example, 32720146 + ... + 33670036.

It is an arithmetic number, because the mean of its divisors is an integer number (1994573722680).

Almost surely, 2^{31531718185081} is an apocalyptic number.

It is an amenable number.

31531718185081 is a deficient number, since it is larger than the sum of its proper divisors (381461377799).

31531718185081 is a wasteful number, since it uses less digits than its factorization.

31531718185081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 951264.

The product of its (nonzero) digits is 806400, while the sum is 52.

Adding to 31531718185081 its reverse (18058181713513), we get a palindrome (49589899898594).

The spelling of 31531718185081 in words is "thirty-one trillion, five hundred thirty-one billion, seven hundred eighteen million, one hundred eighty-five thousand, eighty-one".