21614209 has 2 divisors, whose sum is σ = 21614210. Its totient is φ = 21614208.

The previous prime is 21614183. The next prime is 21614213. The reversal of 21614209 is 90241612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21594609 + 19600 = 4647^2 + 140^2 .

It is a cyclic number.

It is not a de Polignac number, because 21614209 - 2¹⁹ = 21089921 is a prime.

It is not a weakly prime, because it can be changed into another prime (21618209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10807104 + 10807105.

It is an arithmetic number, because the mean of its divisors is an integer number (10807105).

Almost surely, 2^21614209 is an apocalyptic number.

It is an amenable number.

21614209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21614209 is an equidigital number, since it uses as much as digits as its factorization.

21614209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21614209 is about 4649.1084091469. The cubic root of 21614209 is about 278.5563836087.

The spelling of 21614209 in words is "twenty-one million, six hundred fourteen thousand, two hundred nine".