81166935781008 has 320 divisors, whose sum is σ = 294053562224640. Its totient is φ = 21082320282240.

The previous prime is 81166935781003. The next prime is 81166935781037. The reversal of 81166935781008 is 80018753966118.

81166935781008 is a `hidden beast` number, since 8 + 116 + 69 + 357 + 8 + 100 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (81166935781003) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12367860 + ... + 17756627.

It is an arithmetic number, because the mean of its divisors is an integer number (918917381952).

Almost surely, 2^{81166935781008} is an apocalyptic number.

81166935781008 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

81166935781008 is an abundant number, since it is smaller than the sum of its proper divisors (212886626443632).

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

81166935781008 is a wasteful number, since it uses less digits than its factorization.

81166935781008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30124534 (or 30124510 counting only the distinct ones).

The product of its (nonzero) digits is 17418240, while the sum is 63.

The spelling of 81166935781008 in words is "eighty-one trillion, one hundred sixty-six billion, nine hundred thirty-five million, seven hundred eighty-one thousand, eight".