209671992671 has 4 divisors (see below), whose sum is σ = 209689537200. Its totient is φ = 209654448144.

The previous prime is 209671992661. The next prime is 209671992683. The reversal of 209671992671 is 176299176902.

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

It is a cyclic number.

It is not a de Polignac number, because 209671992671 - 2²² = 209667798367 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 209671992671.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209671992611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8754326 + ... + 8778243.

It is an arithmetic number, because the mean of its divisors is an integer number (52422384300).

Almost surely, 2^209671992671 is an apocalyptic number.

209671992671 is a deficient number, since it is larger than the sum of its proper divisors (17544529).

209671992671 is a wasteful number, since it uses less digits than its factorization.

209671992671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17544528.

The product of its (nonzero) digits is 5143824, while the sum is 59.

The spelling of 209671992671 in words is "two hundred nine billion, six hundred seventy-one million, nine hundred ninety-two thousand, six hundred seventy-one".