21804329 has 2 divisors, whose sum is σ = 21804330. Its totient is φ = 21804328.

The previous prime is 21804283. The next prime is 21804331. The reversal of 21804329 is 92340812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18835600 + 2968729 = 4340^2 + 1723^2 .

It is a cyclic number.

It is not a de Polignac number, because 21804329 - 2⁸ = 21804073 is a prime.

Together with 21804331, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21800329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10902164 + 10902165.

It is an arithmetic number, because the mean of its divisors is an integer number (10902165).

Almost surely, 2^21804329 is an apocalyptic number.

It is an amenable number.

21804329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21804329 is an equidigital number, since it uses as much as digits as its factorization.

21804329 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21804329 is about 4669.5105739253. The cubic root of 21804329 is about 279.3707339692.

The spelling of 21804329 in words is "twenty-one million, eight hundred four thousand, three hundred twenty-nine".