81744347509 has 16 divisors (see below), whose sum is σ = 89843060160. Its totient is φ = 73757180160.

The previous prime is 81744347497. The next prime is 81744347519. The reversal of 81744347509 is 90574344718.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81744347509 - 2¹³ = 81744339317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81744347519) 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 15 ways as a sum of consecutive naturals, for example, 8094067 + ... + 8104159.

It is an arithmetic number, because the mean of its divisors is an integer number (5615191260).

Almost surely, 2^81744347509 is an apocalyptic number.

It is an amenable number.

81744347509 is a deficient number, since it is larger than the sum of its proper divisors (8098712651).

81744347509 is a wasteful number, since it uses less digits than its factorization.

81744347509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15540.

The product of its (nonzero) digits is 3386880, while the sum is 52.

The spelling of 81744347509 in words is "eighty-one billion, seven hundred forty-four million, three hundred forty-seven thousand, five hundred nine".