209901 has 16 divisors (see below), whose sum is σ = 301568. Its totient is φ = 129600.

The previous prime is 209887. The next prime is 209917. The reversal of 209901 is 109902.

It is a happy number.

It is not a de Polignac number, because 209901 - 2⁶ = 209837 is a prime.

It is a Curzon number.

It is a plaindrome in base 11 and base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3411 + ... + 3471.

It is an arithmetic number, because the mean of its divisors is an integer number (18848).

2²⁰⁹⁹⁰¹ is an apocalyptic number.

It is an amenable number.

209901 is a deficient number, since it is larger than the sum of its proper divisors (91667).

209901 is a wasteful number, since it uses less digits than its factorization.

209901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 209901 is about 458.1495389062. The cubic root of 209901 is about 59.4298776107.

Subtracting from 209901 its reverse (109902), we obtain a palindrome (99999).

The spelling of 209901 in words is "two hundred nine thousand, nine hundred one".