81413913 has 16 divisors (see below), whose sum is σ = 124185600. Its totient is φ = 46474896.

The previous prime is 81413909. The next prime is 81413929. The reversal of 81413913 is 31931418.

It is not a de Polignac number, because 81413913 - 2² = 81413909 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81413903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37738 + ... + 39836.

It is an arithmetic number, because the mean of its divisors is an integer number (7761600).

Almost surely, 2^81413913 is an apocalyptic number.

It is an amenable number.

81413913 is a deficient number, since it is larger than the sum of its proper divisors (42771687).

81413913 is a wasteful number, since it uses less digits than its factorization.

81413913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3956.

The product of its digits is 2592, while the sum is 30.

The square root of 81413913 is about 9022.9658649471. The cubic root of 81413913 is about 433.4106141590.

The spelling of 81413913 in words is "eighty-one million, four hundred thirteen thousand, nine hundred thirteen".