81318413 has 24 divisors (see below), whose sum is σ = 92951040. Its totient is φ = 71042400.

The previous prime is 81318403. The next prime is 81318421. The reversal of 81318413 is 31481318.

It is not a de Polignac number, because 81318413 - 2¹⁰ = 81317389 is a prime.

It is a super-2 number, since 2×81318413² = 13225368585677138, 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 (81318403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 449183 + ... + 449363.

It is an arithmetic number, because the mean of its divisors is an integer number (3872960).

Almost surely, 2^81318413 is an apocalyptic number.

It is an amenable number.

81318413 is a deficient number, since it is larger than the sum of its proper divisors (11632627).

81318413 is a wasteful number, since it uses less digits than its factorization.

81318413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329 (or 318 counting only the distinct ones).

The product of its digits is 2304, while the sum is 29.

The square root of 81318413 is about 9017.6722606225. The cubic root of 81318413 is about 433.2410816770.

The spelling of 81318413 in words is "eighty-one million, three hundred eighteen thousand, four hundred thirteen".