81315055826 has 8 divisors (see below), whose sum is σ = 129147441660. Its totient is φ = 38265908608.

The previous prime is 81315055793. The next prime is 81315055849. The reversal of 81315055826 is 62855051318.

It can be written as a sum of positive squares in 2 ways, for example, as 81290563225 + 24492601 = 285115^2 + 4949^2 .

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

It is a super-2 number, since 2×81315055826² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1195809611 + ... + 1195809678.

Almost surely, 2^81315055826 is an apocalyptic number.

81315055826 is a deficient number, since it is larger than the sum of its proper divisors (47832385834).

81315055826 is a wasteful number, since it uses less digits than its factorization.

81315055826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2391619308.

The product of its (nonzero) digits is 288000, while the sum is 44.

The spelling of 81315055826 in words is "eighty-one billion, three hundred fifteen million, fifty-five thousand, eight hundred twenty-six".