81317485 has 8 divisors (see below), whose sum is σ = 97633656. Its totient is φ = 65018880.

The previous prime is 81317461. The next prime is 81317491. The reversal of 81317485 is 58471318.

It can be written as a sum of positive squares in 4 ways, for example, as 2569609 + 78747876 = 1603^2 + 8874^2 .

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

It is a de Polignac number, because none of the positive numbers 2^k-81317485 is a prime.

It is a super-2 number, since 2×81317485² = 13225066733450450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10225 + ... + 16345.

It is an arithmetic number, because the mean of its divisors is an integer number (12204207).

Almost surely, 2^81317485 is an apocalyptic number.

It is an amenable number.

81317485 is a deficient number, since it is larger than the sum of its proper divisors (16316171).

81317485 is a wasteful number, since it uses less digits than its factorization.

81317485 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8783.

The product of its digits is 26880, while the sum is 37.

The square root of 81317485 is about 9017.6208059554. The cubic root of 81317485 is about 433.2394336318.

The spelling of 81317485 in words is "eighty-one million, three hundred seventeen thousand, four hundred eighty-five".