81541724919 has 8 divisors (see below), whose sum is σ = 111374063472. Its totient is φ = 53035268160.

The previous prime is 81541724917. The next prime is 81541724921. The reversal of 81541724919 is 91942714518.

It is an interprime number because it is at equal distance from previous prime (81541724917) and next prime (81541724921).

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

It is not a de Polignac number, because 81541724919 - 2¹ = 81541724917 is a prime.

It is a super-2 number, since 2×81541724919² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81541724917) 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, 331470304 + ... + 331470549.

It is an arithmetic number, because the mean of its divisors is an integer number (13921757934).

Almost surely, 2^81541724919 is an apocalyptic number.

81541724919 is a deficient number, since it is larger than the sum of its proper divisors (29832338553).

81541724919 is a wasteful number, since it uses less digits than its factorization.

81541724919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662940897.

The product of its digits is 725760, while the sum is 51.

The spelling of 81541724919 in words is "eighty-one billion, five hundred forty-one million, seven hundred twenty-four thousand, nine hundred nineteen".