71681917 has 4 divisors (see below), whose sum is σ = 73034460. Its totient is φ = 70329376.

The previous prime is 71681887. The next prime is 71681921. The reversal of 71681917 is 71918617.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71918617 = 103 ⋅698239.

It can be written as a sum of positive squares in 2 ways, for example, as 63266116 + 8415801 = 7954^2 + 2901^2 .

It is a cyclic number.

It is not a de Polignac number, because 71681917 - 2¹¹ = 71679869 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71681917.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71681957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 676192 + ... + 676297.

It is an arithmetic number, because the mean of its divisors is an integer number (18258615).

Almost surely, 2^71681917 is an apocalyptic number.

It is an amenable number.

71681917 is a deficient number, since it is larger than the sum of its proper divisors (1352543).

71681917 is a wasteful number, since it uses less digits than its factorization.

71681917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1352542.

The product of its digits is 21168, while the sum is 40.

The square root of 71681917 is about 8466.5174068208. The cubic root of 71681917 is about 415.4032312442.

The spelling of 71681917 in words is "seventy-one million, six hundred eighty-one thousand, nine hundred seventeen".