671636165 has 4 divisors (see below), whose sum is σ = 805963404. Its totient is φ = 537308928.

The previous prime is 671636137. The next prime is 671636167. The reversal of 671636165 is 561636176.

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 511031236 + 160604929 = 22606^2 + 12673^2 .

It is a cyclic number.

It is not a de Polignac number, because 671636165 - 2²⁴ = 654858949 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 (671636167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67163612 + ... + 67163621.

It is an arithmetic number, because the mean of its divisors is an integer number (201490851).

Almost surely, 2^671636165 is an apocalyptic number.

It is an amenable number.

671636165 is a deficient number, since it is larger than the sum of its proper divisors (134327239).

671636165 is a wasteful number, since it uses less digits than its factorization.

671636165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134327238.

The product of its digits is 136080, while the sum is 41.

The square root of 671636165 is about 25915.9442235856. The cubic root of 671636165 is about 875.7457218264.

The spelling of 671636165 in words is "six hundred seventy-one million, six hundred thirty-six thousand, one hundred sixty-five".