81641712188140 has 24 divisors (see below), whose sum is σ = 184635872179920. Its totient is φ = 30144632192448.

The previous prime is 81641712188087. The next prime is 81641712188143. The reversal of 81641712188140 is 4188121714618.

It is a super-2 number, since 2×81641712188140² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is not an unprimeable number, because it can be changed into a prime (81641712188143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 157003292410 + ... + 157003292929.

It is an arithmetic number, because the mean of its divisors is an integer number (7693161340830).

Almost surely, 2^{81641712188140} is an apocalyptic number.

It is an amenable number.

81641712188140 is an abundant number, since it is smaller than the sum of its proper divisors (102994159991780).

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

81641712188140 is a wasteful number, since it uses less digits than its factorization.

81641712188140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314006585361 (or 314006585359 counting only the distinct ones).

The product of its (nonzero) digits is 688128, while the sum is 52.

The spelling of 81641712188140 in words is "eighty-one trillion, six hundred forty-one billion, seven hundred twelve million, one hundred eighty-eight thousand, one hundred forty".