21241304209 has 4 divisors (see below), whose sum is σ = 21241636416. Its totient is φ = 21240972004.

The previous prime is 21241304207. The next prime is 21241304213. The reversal of 21241304209 is 90240314212.

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 21241304209 - 2¹ = 21241304207 is a prime.

It is a super-2 number, since 2×21241304209² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21241304207) 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, 36469 + ... + 209314.

It is an arithmetic number, because the mean of its divisors is an integer number (5310409104).

Almost surely, 2^21241304209 is an apocalyptic number.

It is an amenable number.

21241304209 is a deficient number, since it is larger than the sum of its proper divisors (332207).

21241304209 is an equidigital number, since it uses as much as digits as its factorization.

21241304209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332206.

The product of its (nonzero) digits is 3456, while the sum is 28.

The spelling of 21241304209 in words is "twenty-one billion, two hundred forty-one million, three hundred four thousand, two hundred nine".