81169648939728 has 160 divisors (see below), whose sum is σ = 236173724092800. Its totient is φ = 26688643881984.

The previous prime is 81169648939703. The next prime is 81169648939747. The reversal of 81169648939728 is 82793984696118.

81169648939728 is a `hidden beast` number, since 8 + 1 + 1 + 69 + 6 + 489 + 3 + 9 + 72 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7001938 + ... + 14538446.

It is an arithmetic number, because the mean of its divisors is an integer number (1476085775580).

Almost surely, 2^{81169648939728} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81169648939728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118086862046400).

81169648939728 is an abundant number, since it is smaller than the sum of its proper divisors (155004075153072).

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

81169648939728 is a wasteful number, since it uses less digits than its factorization.

81169648939728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7536866 (or 7536854 counting only the distinct ones).

The product of its digits is 2257403904, while the sum is 81.

The spelling of 81169648939728 in words is "eighty-one trillion, one hundred sixty-nine billion, six hundred forty-eight million, nine hundred thirty-nine thousand, seven hundred twenty-eight".