421668 has 72 divisors (see below), whose sum is σ = 1238328. Its totient is φ = 119808.

The previous prime is 421661. The next prime is 421691. The reversal of 421668 is 866124.

It can be written as a sum of positive squares in 4 ways, for example, as 82944 + 338724 = 288^2 + 582^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421661) by changing a digit.

421668 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7930 + ... + 7982.

It is an arithmetic number, because the mean of its divisors is an integer number (17199).

2⁴²¹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 421668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (619164).

421668 is an abundant number, since it is smaller than the sum of its proper divisors (816660).

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

421668 is a wasteful number, since it uses less digits than its factorization.

421668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 88 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 421668 is about 649.3596846125. The cubic root of 421668 is about 74.9877313265.

It can be divided in two parts, 421 and 668, that added together give a square (1089 = 33²).

The spelling of 421668 in words is "four hundred twenty-one thousand, six hundred sixty-eight".