420557 has 2 divisors, whose sum is σ = 420558. Its totient is φ = 420556.

The previous prime is 420551. The next prime is 420569. The reversal of 420557 is 755024.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217156 + 203401 = 466^2 + 451^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-420557 is a prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210278 + 210279.

It is an arithmetic number, because the mean of its divisors is an integer number (210279).

2⁴²⁰⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

420557 is a deficient number, since it is larger than the sum of its proper divisors (1).

420557 is an equidigital number, since it uses as much as digits as its factorization.

420557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1400, while the sum is 23.

The square root of 420557 is about 648.5036622873. The cubic root of 420557 is about 74.9218148190.

It can be divided in two parts, 4 and 20557, that multiplied together give a palindrome (82228).

The spelling of 420557 in words is "four hundred twenty thousand, five hundred fifty-seven".