420210421 has 2 divisors, whose sum is σ = 420210422. Its totient is φ = 420210420.

The previous prime is 420210419. The next prime is 420210431. The reversal of 420210421 is 124012024.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 221682321 + 198528100 = 14889^2 + 14090^2 .

It is a cyclic number.

It is not a de Polignac number, because 420210421 - 2¹ = 420210419 is a prime.

Together with 420210419, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 420210395 and 420210404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420210431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210105210 + 210105211.

It is an arithmetic number, because the mean of its divisors is an integer number (210105211).

Almost surely, 2^420210421 is an apocalyptic number.

It is an amenable number.

420210421 is a deficient number, since it is larger than the sum of its proper divisors (1).

420210421 is an equidigital number, since it uses as much as digits as its factorization.

420210421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 420210421 is about 20499.0346358066. The cubic root of 420210421 is about 749.0122826050.

Adding to 420210421 its reverse (124012024), we get a palindrome (544222445).

The spelling of 420210421 in words is "four hundred twenty million, two hundred ten thousand, four hundred twenty-one".