81782105 has 8 divisors (see below), whose sum is σ = 98214792. Its totient is φ = 65374848.

The previous prime is 81782093. The next prime is 81782111. The reversal of 81782105 is 50128718.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 44462224 + 37319881 = 6668^2 + 6109^2 .

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 81782105 - 2²⁰ = 80733529 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1637 + ... + 12893.

It is an arithmetic number, because the mean of its divisors is an integer number (12276849).

Almost surely, 2^81782105 is an apocalyptic number.

It is an amenable number.

81782105 is a deficient number, since it is larger than the sum of its proper divisors (16432687).

81782105 is a wasteful number, since it uses less digits than its factorization.

81782105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12715.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 81782105 is about 9043.3458962930. The cubic root of 81782105 is about 434.0629938930.

The spelling of 81782105 in words is "eighty-one million, seven hundred eighty-two thousand, one hundred five".