420400621 has 2 divisors, whose sum is σ = 420400622. Its totient is φ = 420400620.

The previous prime is 420400609. The next prime is 420400639. The reversal of 420400621 is 126004024.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 338044996 + 82355625 = 18386^2 + 9075^2 .

It is a cyclic number.

It is not a de Polignac number, because 420400621 - 2²¹ = 418303469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420400691) 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, 210200310 + 210200311.

It is an arithmetic number, because the mean of its divisors is an integer number (210200311).

Almost surely, 2^420400621 is an apocalyptic number.

It is an amenable number.

420400621 is a deficient number, since it is larger than the sum of its proper divisors (1).

420400621 is an equidigital number, since it uses as much as digits as its factorization.

420400621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 420400621 is about 20503.6733538164. The cubic root of 420400621 is about 749.1252741287.

Adding to 420400621 its reverse (126004024), we get a palindrome (546404645).

The spelling of 420400621 in words is "four hundred twenty million, four hundred thousand, six hundred twenty-one".