420805 has 16 divisors (see below), whose sum is σ = 630144.
Its totient is φ = 262080.
The previous prime is 420803. The next prime is 420809. The reversal of 420805 is 508024.
It is a happy number.
It is not a de Polignac number, because 420805 - 21 = 420803 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (420803) 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 in 15 ways as a sum of consecutive naturals, for example, 162 + ... + 931.
It is an arithmetic number, because the mean of its divisors is an integer number (39384).
2420805 is an apocalyptic number.
It is an amenable number.
420805 is a deficient number, since it is larger than the sum of its proper divisors (209339).
420805 is a wasteful number, since it uses less digits than its factorization.
420805 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1116.
The product of its (nonzero) digits is 320, while the sum is 19.
The square root of 420805 is about 648.6948435127.
The cubic root of 420805 is about 74.9365389103.
Adding to 420805 its reverse (508024), we get a palindrome (928829).
It can be divided in two parts, 420 and 805, that added together give a triangular number (1225 = T49).
The spelling of 420805 in words is "four hundred twenty thousand, eight hundred five".