81049719745 has 8 divisors (see below), whose sum is σ = 97303626216. Its totient is φ = 64810467456.

The previous prime is 81049719727. The next prime is 81049719769. The reversal of 81049719745 is 54791794018.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10713906064 + 70335813681 = 103508^2 + 265209^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81049719745 - 2⁵ = 81049719713 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3651372 + ... + 3673501.

It is an arithmetic number, because the mean of its divisors is an integer number (12162953277).

Almost surely, 2^81049719745 is an apocalyptic number.

It is an amenable number.

81049719745 is a deficient number, since it is larger than the sum of its proper divisors (16253906471).

81049719745 is a wasteful number, since it uses less digits than its factorization.

81049719745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7327091.

The product of its (nonzero) digits is 2540160, while the sum is 55.

The spelling of 81049719745 in words is "eighty-one billion, forty-nine million, seven hundred nineteen thousand, seven hundred forty-five".