81318017 has 4 divisors (see below), whose sum is σ = 88710576. Its totient is φ = 73925460.

The previous prime is 81318011. The next prime is 81318019. The reversal of 81318017 is 71081318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81318017 - 2¹⁰ = 81316993 is a prime.

It is a super-2 number, since 2×81318017² = 13225239777624578, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81318011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3696263 + ... + 3696284.

It is an arithmetic number, because the mean of its divisors is an integer number (22177644).

Almost surely, 2^81318017 is an apocalyptic number.

It is an amenable number.

81318017 is a deficient number, since it is larger than the sum of its proper divisors (7392559).

81318017 is a wasteful number, since it uses less digits than its factorization.

81318017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7392558.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 81318017 is about 9017.6503037099. The cubic root of 81318017 is about 433.2403784179.

The spelling of 81318017 in words is "eighty-one million, three hundred eighteen thousand, seventeen".