81717075 has 72 divisors (see below), whose sum is σ = 161503056. Its totient is φ = 39168000.

The previous prime is 81717037. The next prime is 81717133. The reversal of 81717075 is 57071718.

It is not a de Polignac number, because 81717075 - 2¹³ = 81708883 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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 71 ways as a sum of consecutive naturals, for example, 338955 + ... + 339195.

It is an arithmetic number, because the mean of its divisors is an integer number (2243098).

Almost surely, 2^81717075 is an apocalyptic number.

81717075 is a deficient number, since it is larger than the sum of its proper divisors (79785981).

81717075 is a wasteful number, since it uses less digits than its factorization.

81717075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405 (or 397 counting only the distinct ones).

The product of its (nonzero) digits is 13720, while the sum is 36.

The square root of 81717075 is about 9039.7497199867. The cubic root of 81717075 is about 433.9479132915.

The spelling of 81717075 in words is "eighty-one million, seven hundred seventeen thousand, seventy-five".