71541755721 has 12 divisors (see below), whose sum is σ = 103459249348. Its totient is φ = 47638584864.

The previous prime is 71541755671. The next prime is 71541755767. The reversal of 71541755721 is 12755714517.

71541755721 is a `hidden beast` number, since 7 + 1 + 5 + 4 + 1 + 75 + 572 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14533508025 + 57008247696 = 120555^2 + 238764^2 .

It is not a de Polignac number, because 71541755721 - 2⁶ = 71541755657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71541755221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4651810 + ... + 4667163.

Almost surely, 2^71541755721 is an apocalyptic number.

It is an amenable number.

71541755721 is a deficient number, since it is larger than the sum of its proper divisors (31917493627).

71541755721 is a wasteful number, since it uses less digits than its factorization.

71541755721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9319832 (or 9319829 counting only the distinct ones).

The product of its digits is 343000, while the sum is 45.

The spelling of 71541755721 in words is "seventy-one billion, five hundred forty-one million, seven hundred fifty-five thousand, seven hundred twenty-one".