81173172739 has 8 divisors (see below), whose sum is σ = 82185077520. Its totient is φ = 80162075616.

The previous prime is 81173172701. The next prime is 81173172827. The reversal of 81173172739 is 93727137118.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81173172739 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81173172692 and 81173172701.

It is not an unprimeable number, because it can be changed into a prime (81173172439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1617 + ... + 402925.

It is an arithmetic number, because the mean of its divisors is an integer number (10273134690).

Almost surely, 2^81173172739 is an apocalyptic number.

81173172739 is a deficient number, since it is larger than the sum of its proper divisors (1011904781).

81173172739 is a wasteful number, since it uses less digits than its factorization.

81173172739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403829.

The product of its digits is 444528, while the sum is 49.

The spelling of 81173172739 in words is "eighty-one billion, one hundred seventy-three million, one hundred seventy-two thousand, seven hundred thirty-nine".