81641654799120 has 320 divisors, whose sum is σ = 302874827270400. Its totient is φ = 20094208634880.

The previous prime is 81641654799091. The next prime is 81641654799121. The reversal of 81641654799120 is 2199745614618.

81641654799120 is a `hidden beast` number, since 8 + 1 + 6 + 416 + 5 + 4 + 7 + 99 + 120 = 666.

81641654799120 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (63) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81641654799121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 264331180 + ... + 264639860.

It is an arithmetic number, because the mean of its divisors is an integer number (946483835220).

Almost surely, 2^{81641654799120} is an apocalyptic number.

81641654799120 is a gapful number since it is divisible by the number (80) 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 81641654799120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151437413635200).

81641654799120 is an abundant number, since it is smaller than the sum of its proper divisors (221233172471280).

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

81641654799120 is a wasteful number, since it uses less digits than its factorization.

81641654799120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318135 (or 318123 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 63.

The spelling of 81641654799120 in words is "eighty-one trillion, six hundred forty-one billion, six hundred fifty-four million, seven hundred ninety-nine thousand, one hundred twenty".