871665662217561 has 8 divisors (see below), whose sum is σ = 1169623563740544. Its totient is φ = 577409101086480.

The previous prime is 871665662217419. The next prime is 871665662217569. The reversal of 871665662217561 is 165712266566178.

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

It is not a de Polignac number, because 871665662217561 - 2¹³ = 871665662209369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (871665662217569) 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, 925335097425 + ... + 925335098366.

It is an arithmetic number, because the mean of its divisors is an integer number (146202945467568).

Almost surely, 2^{871665662217561} is an apocalyptic number.

It is an amenable number.

871665662217561 is a deficient number, since it is larger than the sum of its proper divisors (297957901522983).

871665662217561 is a wasteful number, since it uses less digits than its factorization.

871665662217561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1850670195951.

The product of its digits is 304819200, while the sum is 69.

The spelling of 871665662217561 in words is "eight hundred seventy-one trillion, six hundred sixty-five billion, six hundred sixty-two million, two hundred seventeen thousand, five hundred sixty-one".