81357168312 has 64 divisors (see below), whose sum is σ = 258276729600. Its totient is φ = 23244904800.

The previous prime is 81357168293. The next prime is 81357168317. The reversal of 81357168312 is 21386175318.

It is a happy number.

81357168312 is a `hidden beast` number, since 8 + 1 + 3 + 571 + 68 + 3 + 12 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81357168317) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26902314 + ... + 26905337.

It is an arithmetic number, because the mean of its divisors is an integer number (4035573900).

Almost surely, 2^81357168312 is an apocalyptic number.

It is an amenable number.

81357168312 is an abundant number, since it is smaller than the sum of its proper divisors (176919561288).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81357168312 is a wasteful number, since it uses less digits than its factorization.

81357168312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53807673 (or 53807663 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The spelling of 81357168312 in words is "eighty-one billion, three hundred fifty-seven million, one hundred sixty-eight thousand, three hundred twelve".