209389081 has 4 divisors (see below), whose sum is σ = 228424464. Its totient is φ = 190353700.

The previous prime is 209389073. The next prime is 209389093. The reversal of 209389081 is 180983902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 209389081 - 2³ = 209389073 is a prime.

It is a super-2 number, since 2×209389081² = 87687574484049122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209389681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9517675 + ... + 9517696.

It is an arithmetic number, because the mean of its divisors is an integer number (57106116).

Almost surely, 2^209389081 is an apocalyptic number.

It is an amenable number.

209389081 is a deficient number, since it is larger than the sum of its proper divisors (19035383).

209389081 is a wasteful number, since it uses less digits than its factorization.

209389081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19035382.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 209389081 is about 14470.2826855594. The cubic root of 209389081 is about 593.8152457792.

The spelling of 209389081 in words is "two hundred nine million, three hundred eighty-nine thousand, eighty-one".