171257817561 has 8 divisors (see below), whose sum is σ = 228350894304. Its totient is φ = 114168309600.

The previous prime is 171257817547. The next prime is 171257817569. The reversal of 171257817561 is 165718752171.

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

It is not a de Polignac number, because 171257817561 - 2⁵ = 171257817529 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (171257817569) 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, 778140 + ... + 973661.

It is an arithmetic number, because the mean of its divisors is an integer number (28543861788).

Almost surely, 2^171257817561 is an apocalyptic number.

It is an amenable number.

171257817561 is a deficient number, since it is larger than the sum of its proper divisors (57093076743).

171257817561 is a wasteful number, since it uses less digits than its factorization.

171257817561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1784391.

The product of its digits is 823200, while the sum is 51.

The spelling of 171257817561 in words is "one hundred seventy-one billion, two hundred fifty-seven million, eight hundred seventeen thousand, five hundred sixty-one".