209942071 has 4 divisors (see below), whose sum is σ = 209984544. Its totient is φ = 209899600.

The previous prime is 209942069. The next prime is 209942111. The reversal of 209942071 is 170249902.

It is a happy number.

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 209942071 - 2¹ = 209942069 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 (209942371) 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, 12670 + ... + 24091.

It is an arithmetic number, because the mean of its divisors is an integer number (52496136).

Almost surely, 2^209942071 is an apocalyptic number.

209942071 is a deficient number, since it is larger than the sum of its proper divisors (42473).

209942071 is an equidigital number, since it uses as much as digits as its factorization.

209942071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42472.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 209942071 is about 14489.3778679417. The cubic root of 209942071 is about 594.3375354159.

The spelling of 209942071 in words is "two hundred nine million, nine hundred forty-two thousand, seventy-one".