421666 has 8 divisors (see below), whose sum is σ = 722880. Its totient is φ = 180708.

The previous prime is 421661. The next prime is 421691. The reversal of 421666 is 666124.

It is a happy number.

421666 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 421666.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15046 + ... + 15073.

It is an arithmetic number, because the mean of its divisors is an integer number (90360).

2⁴²¹⁶⁶⁶ is an apocalyptic number.

421666 is a deficient number, since it is larger than the sum of its proper divisors (301214).

421666 is a wasteful number, since it uses less digits than its factorization.

421666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30128.

The product of its digits is 1728, while the sum is 25.

The square root of 421666 is about 649.3581446321. The cubic root of 421666 is about 74.9876127690.

The spelling of 421666 in words is "four hundred twenty-one thousand, six hundred sixty-six".