21340109 has 4 divisors (see below), whose sum is σ = 24388704. Its totient is φ = 18291516.

The previous prime is 21340093. The next prime is 21340141. The reversal of 21340109 is 90104312.

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 21340109 - 2⁴ = 21340093 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340409) 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, 1524287 + ... + 1524300.

It is an arithmetic number, because the mean of its divisors is an integer number (6097176).

Almost surely, 2^21340109 is an apocalyptic number.

It is an amenable number.

21340109 is a deficient number, since it is larger than the sum of its proper divisors (3048595).

21340109 is an equidigital number, since it uses as much as digits as its factorization.

21340109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3048594.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21340109 is about 4619.5355827182. The cubic root of 21340109 is about 277.3738690377.

The spelling of 21340109 in words is "twenty-one million, three hundred forty thousand, one hundred nine".