81705716 has 6 divisors (see below), whose sum is σ = 142985010. Its totient is φ = 40852856.

The previous prime is 81705713. The next prime is 81705769. The reversal of 81705716 is 61750718.

It can be written as a sum of positive squares in only one way, i.e., 78393316 + 3312400 = 8854^2 + 1820^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81705713) by changing a digit.

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 as a sum of consecutive naturals, namely, 10213211 + ... + 10213218.

It is an arithmetic number, because the mean of its divisors is an integer number (23830835).

Almost surely, 2^81705716 is an apocalyptic number.

It is an amenable number.

81705716 is a deficient number, since it is larger than the sum of its proper divisors (61279294).

81705716 is a wasteful number, since it uses less digits than its factorization.

81705716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20426433 (or 20426431 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 35.

The square root of 81705716 is about 9039.1214174830. The cubic root of 81705716 is about 433.9278055284.

The spelling of 81705716 in words is "eighty-one million, seven hundred five thousand, seven hundred sixteen".