21404653 has 2 divisors, whose sum is σ = 21404654. Its totient is φ = 21404652.

The previous prime is 21404623. The next prime is 21404681. The reversal of 21404653 is 35640412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12866569 + 8538084 = 3587^2 + 2922^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21404653 is a prime.

It is equal to p_1353922 and since 21404653 and 1353922 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21404623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702326 + 10702327.

It is an arithmetic number, because the mean of its divisors is an integer number (10702327).

Almost surely, 2^21404653 is an apocalyptic number.

It is an amenable number.

21404653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21404653 is an equidigital number, since it uses as much as digits as its factorization.

21404653 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 21404653 is about 4626.5162919847. The cubic root of 21404653 is about 277.6532303101.

The spelling of 21404653 in words is "twenty-one million, four hundred four thousand, six hundred fifty-three".