81005458451749 has 8 divisors (see below), whose sum is σ = 91828050067040. Its totient is φ = 70838781479856.

The previous prime is 81005458451719. The next prime is 81005458451809. The reversal of 81005458451749 is 94715485450018.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-81005458451749 is a prime.

It is a super-2 number, since 2×81005458451749² (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 (81005458451719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163978660587 + ... + 163978661080.

It is an arithmetic number, because the mean of its divisors is an integer number (11478506258380).

Almost surely, 2^{81005458451749} is an apocalyptic number.

It is an amenable number.

81005458451749 is a deficient number, since it is larger than the sum of its proper divisors (10822591615291).

81005458451749 is a wasteful number, since it uses less digits than its factorization.

81005458451749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327957321699.

The product of its (nonzero) digits is 32256000, while the sum is 61.

The spelling of 81005458451749 in words is "eighty-one trillion, five billion, four hundred fifty-eight million, four hundred fifty-one thousand, seven hundred forty-nine".