81712145 has 8 divisors (see below), whose sum is σ = 98167680. Its totient is φ = 65294320.

The previous prime is 81712079. The next prime is 81712151. The reversal of 81712145 is 54121718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81712145 - 2¹⁸ = 81450001 is a prime.

It is a Curzon 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, 4415 + ... + 13524.

It is an arithmetic number, because the mean of its divisors is an integer number (12270960).

Almost surely, 2^81712145 is an apocalyptic number.

It is an amenable number.

81712145 is a deficient number, since it is larger than the sum of its proper divisors (16455535).

81712145 is a wasteful number, since it uses less digits than its factorization.

81712145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18855.

The product of its digits is 2240, while the sum is 29.

The square root of 81712145 is about 9039.4770313332. The cubic root of 81712145 is about 433.9391864077.

The spelling of 81712145 in words is "eighty-one million, seven hundred twelve thousand, one hundred forty-five".