81017309 has 8 divisors (see below), whose sum is σ = 83347680. Its totient is φ = 78694416.

The previous prime is 81017303. The next prime is 81017317. The reversal of 81017309 is 90371018.

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-81017309 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81017303) 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, 25862 + ... + 28824.

It is an arithmetic number, because the mean of its divisors is an integer number (10418460).

Almost surely, 2^81017309 is an apocalyptic number.

It is an amenable number.

81017309 is a deficient number, since it is larger than the sum of its proper divisors (2330371).

81017309 is a wasteful number, since it uses less digits than its factorization.

81017309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3739.

The product of its (nonzero) digits is 1512, while the sum is 29.

The square root of 81017309 is about 9000.9615597446. The cubic root of 81017309 is about 432.7056885241.

The spelling of 81017309 in words is "eighty-one million, seventeen thousand, three hundred nine".