71721685188505 has 12 divisors (see below), whose sum is σ = 94601495505636. Its totient is φ = 52161225591200.

The previous prime is 71721685188443. The next prime is 71721685188539. The reversal of 71721685188505 is 50588158612717.

It can be written as a sum of positive squares in 2 ways, for example, as 26864535976201 + 44857149212304 = 5183101^2 + 6697548^2 .

It is not a de Polignac number, because 71721685188505 - 2⁹ = 71721685187993 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59274119386 + ... + 59274120595.

It is an arithmetic number, because the mean of its divisors is an integer number (7883457958803).

Almost surely, 2^{71721685188505} is an apocalyptic number.

It is an amenable number.

71721685188505 is a deficient number, since it is larger than the sum of its proper divisors (22879810317131).

71721685188505 is a wasteful number, since it uses less digits than its factorization.

71721685188505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118548240008 (or 118548239997 counting only the distinct ones).

The product of its (nonzero) digits is 37632000, while the sum is 64.

The spelling of 71721685188505 in words is "seventy-one trillion, seven hundred twenty-one billion, six hundred eighty-five million, one hundred eighty-eight thousand, five hundred five".