21300421 has 2 divisors, whose sum is σ = 21300422. Its totient is φ = 21300420.

The previous prime is 21300403. The next prime is 21300431. The reversal of 21300421 is 12400312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19448100 + 1852321 = 4410^2 + 1361^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21300421 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21300401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650210 + 10650211.

It is an arithmetic number, because the mean of its divisors is an integer number (10650211).

Almost surely, 2^21300421 is an apocalyptic number.

It is an amenable number.

21300421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300421 is an equidigital number, since it uses as much as digits as its factorization.

21300421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21300421 is about 4615.2379136942. The cubic root of 21300421 is about 277.2018104726.

Adding to 21300421 its reverse (12400312), we get a palindrome (33700733).

The spelling of 21300421 in words is "twenty-one million, three hundred thousand, four hundred twenty-one".