81315251318 has 16 divisors (see below), whose sum is σ = 140058230784. Its totient is φ = 34684229160.

The previous prime is 81315251317. The next prime is 81315251321.

81315251318 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×81315251318² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81315251317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13760630 + ... + 13766537.

It is an arithmetic number, because the mean of its divisors is an integer number (8753639424).

Almost surely, 2^81315251318 is an apocalyptic number.

81315251318 is a deficient number, since it is larger than the sum of its proper divisors (58742979466).

81315251318 is a wasteful number, since it uses less digits than its factorization.

81315251318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27527387.

The product of its digits is 28800, while the sum is 38.

The spelling of 81315251318 in words is "eighty-one billion, three hundred fifteen million, two hundred fifty-one thousand, three hundred eighteen".