209541 has 4 divisors (see below), whose sum is σ = 279392. Its totient is φ = 139692.

The previous prime is 209533. The next prime is 209543. The reversal of 209541 is 145902.

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 not a de Polignac number, because 209541 - 2³ = 209533 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209543) 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, 34921 + ... + 34926.

It is an arithmetic number, because the mean of its divisors is an integer number (69848).

2²⁰⁹⁵⁴¹ is an apocalyptic number.

It is an amenable number.

209541 is a deficient number, since it is larger than the sum of its proper divisors (69851).

209541 is an equidigital number, since it uses as much as digits as its factorization.

209541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69850.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 209541 is about 457.7564854811. The cubic root of 209541 is about 59.3958822209.

The spelling of 209541 in words is "two hundred nine thousand, five hundred forty-one".