81398717 has 8 divisors (see below), whose sum is σ = 85800000. Its totient is φ = 77009184.

The previous prime is 81398683. The next prime is 81398729. The reversal of 81398717 is 71789318.

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 81398717 - 2²⁰ = 80350141 is a prime.

It is a super-2 number, since 2×81398717² = 13251502258492178, which 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 (81398767) 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, 13784 + ... + 18782.

It is an arithmetic number, because the mean of its divisors is an integer number (10725000).

Almost surely, 2^81398717 is an apocalyptic number.

It is an amenable number.

81398717 is a deficient number, since it is larger than the sum of its proper divisors (4401283).

81398717 is a wasteful number, since it uses less digits than its factorization.

81398717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5875.

The product of its digits is 84672, while the sum is 44.

The square root of 81398717 is about 9022.1237521994. The cubic root of 81398717 is about 433.3836469522.

The spelling of 81398717 in words is "eighty-one million, three hundred ninety-eight thousand, seven hundred seventeen".