21704369 has 2 divisors, whose sum is σ = 21704370. Its totient is φ = 21704368.

The previous prime is 21704357. The next prime is 21704377. The reversal of 21704369 is 96340712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21669025 + 35344 = 4655^2 + 188^2 .

It is a cyclic number.

It is not a de Polignac number, because 21704369 - 2⁸ = 21704113 is a prime.

It is a super-2 number, since 2×21704369² = 942159267376322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21704399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10852184 + 10852185.

It is an arithmetic number, because the mean of its divisors is an integer number (10852185).

Almost surely, 2^21704369 is an apocalyptic number.

It is an amenable number.

21704369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21704369 is an equidigital number, since it uses as much as digits as its factorization.

21704369 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 21704369 is about 4658.7948012335. The cubic root of 21704369 is about 278.9431631844.

The spelling of 21704369 in words is "twenty-one million, seven hundred four thousand, three hundred sixty-nine".