81172356170724 has 288 divisors, whose sum is σ = 266690967588864. Its totient is φ = 20230591138560.

The previous prime is 81172356170681. The next prime is 81172356170743. The reversal of 81172356170724 is 42707165327118.

81172356170724 is a `hidden beast` number, since 8 + 1 + 1 + 7 + 2 + 3 + 561 + 7 + 0 + 72 + 4 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 235872 + ... + 12743639.

It is an arithmetic number, because the mean of its divisors is an integer number (926010304128).

Almost surely, 2^{81172356170724} is an apocalyptic number.

81172356170724 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81172356170724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133345483794432).

81172356170724 is an abundant number, since it is smaller than the sum of its proper divisors (185518611418140).

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

81172356170724 is a wasteful number, since it uses less digits than its factorization.

81172356170724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12979647 (or 12979642 counting only the distinct ones).

The product of its (nonzero) digits is 3951360, while the sum is 54.

The spelling of 81172356170724 in words is "eighty-one trillion, one hundred seventy-two billion, three hundred fifty-six million, one hundred seventy thousand, seven hundred twenty-four".