421640 has 32 divisors (see below), whose sum is σ = 967680. Its totient is φ = 165312.

The previous prime is 421639. The next prime is 421643. The reversal of 421640 is 46124.

421640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (421643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3257 + ... + 3383.

It is an arithmetic number, because the mean of its divisors is an integer number (30240).

2⁴²¹⁶⁴⁰ is an apocalyptic number.

421640 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 421640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (483840).

421640 is an abundant number, since it is smaller than the sum of its proper divisors (546040).

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

421640 is a wasteful number, since it uses less digits than its factorization.

421640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 421640 is about 649.3381245545. The cubic root of 421640 is about 74.9860714875.

Adding to 421640 its reverse (46124), we get a palindrome (467764).

The spelling of 421640 in words is "four hundred twenty-one thousand, six hundred forty".