81744318431 has 4 divisors (see below), whose sum is σ = 86046651000. Its totient is φ = 77441985864.

The previous prime is 81744318419. The next prime is 81744318473. The reversal of 81744318431 is 13481344718.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81744318431 - 2²⁶ = 81677209567 is a prime.

It is a super-2 number, since 2×81744318431² (a number of 23 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 (81744318401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2151166256 + ... + 2151166293.

It is an arithmetic number, because the mean of its divisors is an integer number (21511662750).

Almost surely, 2^81744318431 is an apocalyptic number.

81744318431 is a deficient number, since it is larger than the sum of its proper divisors (4302332569).

81744318431 is a wasteful number, since it uses less digits than its factorization.

81744318431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4302332568.

The product of its digits is 258048, while the sum is 44.

The spelling of 81744318431 in words is "eighty-one billion, seven hundred forty-four million, three hundred eighteen thousand, four hundred thirty-one".