209012189 has 4 divisors (see below), whose sum is σ = 209825724. Its totient is φ = 208198656.

The previous prime is 209012173. The next prime is 209012191. The reversal of 209012189 is 981210902.

It is a happy number.

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 128640964 + 80371225 = 11342^2 + 8965^2 .

It is a cyclic number.

It is not a de Polignac number, because 209012189 - 2⁴ = 209012173 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 (209012119) 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, 406382 + ... + 406895.

It is an arithmetic number, because the mean of its divisors is an integer number (52456431).

Almost surely, 2^209012189 is an apocalyptic number.

It is an amenable number.

209012189 is a deficient number, since it is larger than the sum of its proper divisors (813535).

209012189 is an equidigital number, since it uses as much as digits as its factorization.

209012189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 813534.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 209012189 is about 14457.2538540347. The cubic root of 209012189 is about 593.4587505431.

The spelling of 209012189 in words is "two hundred nine million, twelve thousand, one hundred eighty-nine".