209543302081 has 9 divisors (see below), whose sum is σ = 222602708899. Its totient is φ = 197209901344.

The previous prime is 209543302061. The next prime is 209543302109. The reversal of 209543302081 is 180203345902.

The square root of 209543302081 is 457759.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 163139249025 + 46404053056 = 403905^2 + 215416^2 .

It is not a de Polignac number, because 209543302081 - 2⁷ = 209543301953 is a prime.

It is a super-2 number, since 2×209543302081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 209543302081.

It is not an unprimeable number, because it can be changed into a prime (209543302061) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 7768440 + ... + 7795366.

Almost surely, 2^209543302081 is an apocalyptic number.

209543302081 is the 457759-th square number.

209543302081 is the 228880-th centered octagonal number.

It is an amenable number.

209543302081 is a deficient number, since it is larger than the sum of its proper divisors (13059406818).

209543302081 is an frugal number, since it uses more digits than its factorization.

209543302081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53888 (or 26944 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 37.

Adding to 209543302081 its reverse (180203345902), we get a palindrome (389746647983).

The spelling of 209543302081 in words is "two hundred nine billion, five hundred forty-three million, three hundred two thousand, eighty-one".