81536491108 has 12 divisors (see below), whose sum is σ = 142691013612. Its totient is φ = 40767630080.

The previous prime is 81536491087. The next prime is 81536491117. The reversal of 81536491108 is 80119463518.

It can be written as a sum of positive squares in 2 ways, for example, as 6521854564 + 75014636544 = 80758^2 + 273888^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 280368 + ... + 491608.

It is an arithmetic number, because the mean of its divisors is an integer number (11890917801).

Almost surely, 2^81536491108 is an apocalyptic number.

It is an amenable number.

81536491108 is a deficient number, since it is larger than the sum of its proper divisors (61154522504).

81536491108 is a wasteful number, since it uses less digits than its factorization.

81536491108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307742 (or 307740 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 46.

The spelling of 81536491108 in words is "eighty-one billion, five hundred thirty-six million, four hundred ninety-one thousand, one hundred eight".