71681543 has 4 divisors (see below), whose sum is σ = 73618920. Its totient is φ = 69744168.

The previous prime is 71681521. The next prime is 71681549. The reversal of 71681543 is 34518617.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34518617 = 7 ⋅4931231.

It is a cyclic number.

It is not a de Polignac number, because 71681543 - 2⁶ = 71681479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71681549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 968633 + ... + 968706.

It is an arithmetic number, because the mean of its divisors is an integer number (18404730).

Almost surely, 2^71681543 is an apocalyptic number.

71681543 is a deficient number, since it is larger than the sum of its proper divisors (1937377).

71681543 is a wasteful number, since it uses less digits than its factorization.

71681543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1937376.

The product of its digits is 20160, while the sum is 35.

The square root of 71681543 is about 8466.4953197885. The cubic root of 71681543 is about 415.4025087883.

The spelling of 71681543 in words is "seventy-one million, six hundred eighty-one thousand, five hundred forty-three".