21341209 has 4 divisors (see below), whose sum is σ = 21598416. Its totient is φ = 21084004.

The previous prime is 21341191. The next prime is 21341249. The reversal of 21341209 is 90214312.

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 21341209 - 2⁷ = 21341081 is a prime.

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 21341209.

It is not an unprimeable number, because it can be changed into a prime (21341249) 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, 128479 + ... + 128644.

It is an arithmetic number, because the mean of its divisors is an integer number (5399604).

Almost surely, 2^21341209 is an apocalyptic number.

It is an amenable number.

21341209 is a deficient number, since it is larger than the sum of its proper divisors (257207).

21341209 is an equidigital number, since it uses as much as digits as its factorization.

21341209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257206.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21341209 is about 4619.6546407713. The cubic root of 21341209 is about 277.3786348055.

The spelling of 21341209 in words is "twenty-one million, three hundred forty-one thousand, two hundred nine".