209129071 has 4 divisors (see below), whose sum is σ = 209332944. Its totient is φ = 208925200.

The previous prime is 209129051. The next prime is 209129083. The reversal of 209129071 is 170921902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 170921902 = 2 ⋅85460951.

It is a cyclic number.

It is not a de Polignac number, because 209129071 - 2⁷ = 209128943 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 (209129051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 100390 + ... + 102451.

It is an arithmetic number, because the mean of its divisors is an integer number (52333236).

Almost surely, 2^209129071 is an apocalyptic number.

209129071 is a deficient number, since it is larger than the sum of its proper divisors (203873).

209129071 is a wasteful number, since it uses less digits than its factorization.

209129071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203872.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 209129071 is about 14461.2956196877. The cubic root of 209129071 is about 593.5693528964.

The spelling of 209129071 in words is "two hundred nine million, one hundred twenty-nine thousand, seventy-one".