81316913 has 8 divisors (see below), whose sum is σ = 83652096. Its totient is φ = 79002000.

The previous prime is 81316889. The next prime is 81316919. The reversal of 81316913 is 31961318.

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 81316913 - 2⁶ = 81316849 is a prime.

It is a super-2 number, since 2×81316913² = 13224880679699138, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81316913.

It is not an unprimeable number, because it can be changed into a prime (81316919) 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, 3263 + ... + 13163.

It is an arithmetic number, because the mean of its divisors is an integer number (10456512).

Almost surely, 2^81316913 is an apocalyptic number.

It is an amenable number.

81316913 is a deficient number, since it is larger than the sum of its proper divisors (2335183).

81316913 is a wasteful number, since it uses less digits than its factorization.

81316913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10135.

The product of its digits is 3888, while the sum is 32.

The square root of 81316913 is about 9017.5890902170. The cubic root of 81316913 is about 433.2384178046.

The spelling of 81316913 in words is "eighty-one million, three hundred sixteen thousand, nine hundred thirteen".