21300052421 has 2 divisors, whose sum is σ = 21300052422. Its totient is φ = 21300052420.

The previous prime is 21300052387. The next prime is 21300052427. The reversal of 21300052421 is 12425000312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17189832100 + 4110220321 = 131110^2 + 64111^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300052421 - 2⁶ = 21300052357 is a prime.

It is a super-2 number, since 2×21300052421² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21300052393 and 21300052402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21300052427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650026210 + 10650026211.

It is an arithmetic number, because the mean of its divisors is an integer number (10650026211).

Almost surely, 2^21300052421 is an apocalyptic number.

It is an amenable number.

21300052421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300052421 is an equidigital number, since it uses as much as digits as its factorization.

21300052421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 21300052421 its reverse (12425000312), we get a palindrome (33725052733).

The spelling of 21300052421 in words is "twenty-one billion, three hundred million, fifty-two thousand, four hundred twenty-one".