71728780717 has 8 divisors (see below), whose sum is σ = 78344898912. Its totient is φ = 65128549200.

The previous prime is 71728780681. The next prime is 71728780729. The reversal of 71728780717 is 71708782717.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-71728780717 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 (71728780787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3962223 + ... + 3980284.

It is an arithmetic number, because the mean of its divisors is an integer number (9793112364).

Almost surely, 2^71728780717 is an apocalyptic number.

It is an amenable number.

71728780717 is a deficient number, since it is larger than the sum of its proper divisors (6616118195).

71728780717 is a wasteful number, since it uses less digits than its factorization.

71728780717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7943339.

The product of its (nonzero) digits is 2151296, while the sum is 55.

The spelling of 71728780717 in words is "seventy-one billion, seven hundred twenty-eight million, seven hundred eighty thousand, seven hundred seventeen".