81872199843840 has 4096 divisors, whose sum is σ = 378327158784000. Its totient is φ = 16361812131840.

The previous prime is 81872199843827. The next prime is 81872199843881. The reversal of 81872199843840 is 4834899127818.

81872199843840 is a `hidden beast` number, since 8 + 1 + 87 + 2 + 1 + 99 + 84 + 384 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (4096).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 473249709994 + ... + 473249710166.

It is an arithmetic number, because the mean of its divisors is an integer number (92365029000).

Almost surely, 2^{81872199843840} is an apocalyptic number.

81872199843840 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 81872199843840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189163579392000).

81872199843840 is an abundant number, since it is smaller than the sum of its proper divisors (296454958940160).

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

81872199843840 is a wasteful number, since it uses less digits than its factorization.

81872199843840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 222953472, while the sum is 72.

The spelling of 81872199843840 in words is "eighty-one trillion, eight hundred seventy-two billion, one hundred ninety-nine million, eight hundred forty-three thousand, eight hundred forty".