421720 has 32 divisors (see below), whose sum is σ = 1023120. Its totient is φ = 155520.

The previous prime is 421717. The next prime is 421727. The reversal of 421720 is 27124.

It is a junction number, because it is equal to n+sod(n) for n = 421694 and 421703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421727) 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 7 ways as a sum of consecutive naturals, for example, 115 + ... + 925.

2⁴²¹⁷²⁰ is an apocalyptic number.

421720 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 421720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (511560).

421720 is an abundant number, since it is smaller than the sum of its proper divisors (601400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

421720 is a wasteful number, since it uses less digits than its factorization.

421720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 835 (or 831 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 421720 is about 649.3997228210. The cubic root of 421720 is about 74.9908136897.

Adding to 421720 its reverse (27124), we get a palindrome (448844).

The spelling of 421720 in words is "four hundred twenty-one thousand, seven hundred twenty", and thus it is an iban number.