81319281443 has 4 divisors (see below), whose sum is σ = 81579087768. Its totient is φ = 81059475120.

The previous prime is 81319281383. The next prime is 81319281479. The reversal of 81319281443 is 34418291318.

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 81319281443 - 2⁸ = 81319281187 is a prime.

It is a super-2 number, since 2×81319281443² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81319281394 and 81319281403.

It is not an unprimeable number, because it can be changed into a prime (81319281343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129902693 + ... + 129903318.

It is an arithmetic number, because the mean of its divisors is an integer number (20394771942).

Almost surely, 2^81319281443 is an apocalyptic number.

81319281443 is a deficient number, since it is larger than the sum of its proper divisors (259806325).

81319281443 is a wasteful number, since it uses less digits than its factorization.

81319281443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259806324.

The product of its digits is 165888, while the sum is 44.

The spelling of 81319281443 in words is "eighty-one billion, three hundred nineteen million, two hundred eighty-one thousand, four hundred forty-three".