81178313868 has 72 divisors (see below), whose sum is σ = 206696977760. Its totient is φ = 26862451200.

The previous prime is 81178313831. The next prime is 81178313899. The reversal of 81178313868 is 86831387118.

It is a happy number.

81178313868 is a `hidden beast` number, since 81 + 178 + 313 + 86 + 8 = 666.

It is a super-3 number, since 3×81178313868³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 23 ways as a sum of consecutive naturals, for example, 6782073 + ... + 6794031.

Almost surely, 2^81178313868 is an apocalyptic number.

It is an amenable number.

81178313868 is an abundant number, since it is smaller than the sum of its proper divisors (125518663892).

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

81178313868 is a wasteful number, since it uses less digits than its factorization.

81178313868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13327 (or 13322 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 54.

The spelling of 81178313868 in words is "eighty-one billion, one hundred seventy-eight million, three hundred thirteen thousand, eight hundred sixty-eight".