31381618861 has 8 divisors (see below), whose sum is σ = 31441332600. Its totient is φ = 31321958400.

The previous prime is 31381618841. The next prime is 31381618871. The reversal of 31381618861 is 16881618313.

It can be written as a sum of positive squares in 4 ways, for example, as 14661577225 + 16720041636 = 121085^2 + 129306^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31381618861 - 2²¹ = 31379521709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31381618841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1283095 + ... + 1307323.

It is an arithmetic number, because the mean of its divisors is an integer number (3930166575).

Almost surely, 2^31381618861 is an apocalyptic number.

It is an amenable number.

31381618861 is a deficient number, since it is larger than the sum of its proper divisors (59713739).

31381618861 is a wasteful number, since it uses less digits than its factorization.

31381618861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26639.

The product of its digits is 165888, while the sum is 46.

The spelling of 31381618861 in words is "thirty-one billion, three hundred eighty-one million, six hundred eighteen thousand, eight hundred sixty-one".