421644 has 24 divisors (see below), whose sum is σ = 1009008. Its totient is φ = 136960.

The previous prime is 421643. The next prime is 421657. The reversal of 421644 is 446124.

It is a nude number because it is divisible by every one of its digits.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 421644.

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, 64 + ... + 920.

It is an arithmetic number, because the mean of its divisors is an integer number (42042).

2⁴²¹⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

421644 is an abundant number, since it is smaller than the sum of its proper divisors (587364).

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

421644 is a wasteful number, since it uses less digits than its factorization.

421644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 905 (or 903 counting only the distinct ones).

The product of its digits is 768, while the sum is 21.

The square root of 421644 is about 649.3412046066. The cubic root of 421644 is about 74.9863086119.

Adding to 421644 its reverse (446124), we get a palindrome (867768).

The spelling of 421644 in words is "four hundred twenty-one thousand, six hundred forty-four".