81888445 has 8 divisors (see below), whose sum is σ = 100120536. Its totient is φ = 64274496.

The previous prime is 81888427. The next prime is 81888451. The reversal of 81888445 is 54488818.

It can be written as a sum of positive squares in 4 ways, for example, as 10621081 + 71267364 = 3259^2 + 8442^2 .

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 81888445 - 2¹⁵ = 81855677 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81888395 and 81888404.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 154242 + ... + 154771.

It is an arithmetic number, because the mean of its divisors is an integer number (12515067).

Almost surely, 2^81888445 is an apocalyptic number.

It is an amenable number.

81888445 is a deficient number, since it is larger than the sum of its proper divisors (18232091).

81888445 is a wasteful number, since it uses less digits than its factorization.

81888445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309071.

The product of its digits is 327680, while the sum is 46.

The square root of 81888445 is about 9049.2234473462. The cubic root of 81888445 is about 434.2510475302.

The spelling of 81888445 in words is "eighty-one million, eight hundred eighty-eight thousand, four hundred forty-five".