84171517861 has 4 divisors (see below), whose sum is σ = 84174827212. Its totient is φ = 84168208512.

The previous prime is 84171517849. The next prime is 84171517907. The reversal of 84171517861 is 16871517148.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 63028613025 + 21142904836 = 251055^2 + 145406^2 .

It is a cyclic number.

It is not a de Polignac number, because 84171517861 - 2³³ = 75581583269 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 (84171517961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1616226 + ... + 1667491.

It is an arithmetic number, because the mean of its divisors is an integer number (21043706803).

Almost surely, 2^84171517861 is an apocalyptic number.

It is an amenable number.

84171517861 is a deficient number, since it is larger than the sum of its proper divisors (3309351).

84171517861 is a wasteful number, since it uses less digits than its factorization.

84171517861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3309350.

The product of its digits is 376320, while the sum is 49.

The spelling of 84171517861 in words is "eighty-four billion, one hundred seventy-one million, five hundred seventeen thousand, eight hundred sixty-one".