31581129244681 has 3 divisors (see below), whose sum is σ = 31581134864391. Its totient is φ = 31581123624972.

The previous prime is 31581129244673. The next prime is 31581129244699. The reversal of 31581129244681 is 18644292118513.

The square root of 31581129244681 is 5619709.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 31518017756281 + 63111488400 = 5614091^2 + 251220^2 .

It is not a de Polignac number, because 31581129244681 - 2³ = 31581129244673 is a prime.

It is a super-3 number, since 3×31581129244681³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31581129244081) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2809855 + ... + 8429563.

It is an arithmetic number, because the mean of its divisors is an integer number (10527044954797).

Almost surely, 2^{31581129244681} is an apocalyptic number.

31581129244681 is the 5619709-th square number.

31581129244681 is the 2809855-th centered octagonal number.

It is an amenable number.

31581129244681 is a deficient number, since it is larger than the sum of its proper divisors (5619710).

31581129244681 is an frugal number, since it uses more digits than its factorization.

31581129244681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11239418 (or 5619709 counting only the distinct ones).

The product of its digits is 3317760, while the sum is 55.

The spelling of 31581129244681 in words is "thirty-one trillion, five hundred eighty-one billion, one hundred twenty-nine million, two hundred forty-four thousand, six hundred eighty-one".