81443741524993 has 4 divisors (see below), whose sum is σ = 81446749408980. Its totient is φ = 81440733641008.

The previous prime is 81443741524963. The next prime is 81443741525009. The reversal of 81443741524993 is 39942514734418.

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

It can be written as a sum of positive squares in 2 ways, for example, as 75853770291649 + 5589971233344 = 8709407^2 + 2364312^2 .

It is a cyclic number.

It is not a de Polignac number, because 81443741524993 - 2¹⁷ = 81443741393921 is a prime.

It is a super-2 number, since 2×81443741524993² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81443741524933) 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, 1503901378 + ... + 1503955531.

It is an arithmetic number, because the mean of its divisors is an integer number (20361687352245).

Almost surely, 2^{81443741524993} is an apocalyptic number.

It is an amenable number.

81443741524993 is a deficient number, since it is larger than the sum of its proper divisors (3007883987).

81443741524993 is a wasteful number, since it uses less digits than its factorization.

81443741524993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3007883986.

The product of its digits is 104509440, while the sum is 64.

The spelling of 81443741524993 in words is "eighty-one trillion, four hundred forty-three billion, seven hundred forty-one million, five hundred twenty-four thousand, nine hundred ninety-three".