21204329 has 2 divisors, whose sum is σ = 21204330. Its totient is φ = 21204328.

The previous prime is 21204251. The next prime is 21204347. The reversal of 21204329 is 92340212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16386304 + 4818025 = 4048^2 + 2195^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204329 - 2¹² = 21200233 is a prime.

It is equal to p_1342049 and since 21204329 and 1342049 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21204349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602164 + 10602165.

It is an arithmetic number, because the mean of its divisors is an integer number (10602165).

Almost surely, 2^21204329 is an apocalyptic number.

It is an amenable number.

21204329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204329 is an equidigital number, since it uses as much as digits as its factorization.

21204329 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21204329 is about 4604.8158486524. The cubic root of 21204329 is about 276.7843377778.

The spelling of 21204329 in words is "twenty-one million, two hundred four thousand, three hundred twenty-nine".