6667172171665 has 4 divisors (see below), whose sum is σ = 8000606606004. Its totient is φ = 5333737737328.

The previous prime is 6667172171533. The next prime is 6667172171683. The reversal of 6667172171665 is 5661712717666.

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 1367194671441 + 5299977500224 = 1169271^2 + 2302168^2 .

It is a cyclic number.

It is not a de Polignac number, because 6667172171665 - 2²⁵ = 6667138617233 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 666717217162 + ... + 666717217171.

It is an arithmetic number, because the mean of its divisors is an integer number (2000151651501).

Almost surely, 2^{6667172171665} is an apocalyptic number.

It is an amenable number.

6667172171665 is a deficient number, since it is larger than the sum of its proper divisors (1333434434339).

6667172171665 is a wasteful number, since it uses less digits than its factorization.

6667172171665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333434434338.

The product of its digits is 26671680, while the sum is 61.

It can be divided in two parts, 666717 and 2171665, that added together give a palindrome (2838382).

The spelling of 6667172171665 in words is "six trillion, six hundred sixty-seven billion, one hundred seventy-two million, one hundred seventy-one thousand, six hundred sixty-five".