209481 has 4 divisors (see below), whose sum is σ = 279312. Its totient is φ = 139652.

The previous prime is 209477. The next prime is 209497. The reversal of 209481 is 184902.

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 209481 - 2² = 209477 is a prime.

It is a super-2 number, since 2×209481² = 87764578722, which contains 22 as substring.

It is a D-number.

209481 is a lucky number.

It is a nialpdrome in base 8.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 209481.

It is not an unprimeable number, because it can be changed into a prime (209401) 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, 34911 + ... + 34916.

It is an arithmetic number, because the mean of its divisors is an integer number (69828).

2²⁰⁹⁴⁸¹ is an apocalyptic number.

It is an amenable number.

209481 is a deficient number, since it is larger than the sum of its proper divisors (69831).

209481 is an equidigital number, since it uses as much as digits as its factorization.

209481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69830.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 209481 is about 457.6909437601. The cubic root of 209481 is about 59.3902125379.

The spelling of 209481 in words is "two hundred nine thousand, four hundred eighty-one".