81888313 has 8 divisors (see below), whose sum is σ = 88445000. Its totient is φ = 75368448.

The previous prime is 81888311. The next prime is 81888353. The reversal of 81888313 is 31388818.

It can be written as a sum of positive squares in 4 ways, for example, as 20548089 + 61340224 = 4533^2 + 7832^2 .

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 81888313 - 2¹ = 81888311 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81888311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4488 + ... + 13561.

It is an arithmetic number, because the mean of its divisors is an integer number (11055625).

Almost surely, 2^81888313 is an apocalyptic number.

It is an amenable number.

81888313 is a deficient number, since it is larger than the sum of its proper divisors (6556687).

81888313 is a wasteful number, since it uses less digits than its factorization.

81888313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18411.

The product of its digits is 36864, while the sum is 40.

The square root of 81888313 is about 9049.2161538997. The cubic root of 81888313 is about 434.2508141999.

The spelling of 81888313 in words is "eighty-one million, eight hundred eighty-eight thousand, three hundred thirteen".