81441918721199 has 8 divisors (see below), whose sum is σ = 87646269328848. Its totient is φ = 75394640280960.

The previous prime is 81441918721187. The next prime is 81441918721223. The reversal of 81441918721199 is 99112781914418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81441918721199 - 2⁴ = 81441918721183 is a prime.

It is a super-2 number, since 2×81441918721199² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81441918721139) 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, 39268040777 + ... + 39268042850.

It is an arithmetic number, because the mean of its divisors is an integer number (10955783666106).

Almost surely, 2^{81441918721199} is an apocalyptic number.

81441918721199 is a deficient number, since it is larger than the sum of its proper divisors (6204350607649).

81441918721199 is a wasteful number, since it uses less digits than its factorization.

81441918721199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78536083705.

The product of its digits is 10450944, while the sum is 65.

The spelling of 81441918721199 in words is "eighty-one trillion, four hundred forty-one billion, nine hundred eighteen million, seven hundred twenty-one thousand, one hundred ninety-nine".