421663 has 4 divisors (see below), whose sum is σ = 460008. Its totient is φ = 383320.

The previous prime is 421661. The next prime is 421691. The reversal of 421663 is 366124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 421663 - 2¹ = 421661 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

421663 is a lucky number.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19156 + ... + 19177.

It is an arithmetic number, because the mean of its divisors is an integer number (115002).

2⁴²¹⁶⁶³ is an apocalyptic number.

421663 is a deficient number, since it is larger than the sum of its proper divisors (38345).

421663 is a wasteful number, since it uses less digits than its factorization.

421663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38344.

The product of its digits is 864, while the sum is 22.

The square root of 421663 is about 649.3558346546. The cubic root of 421663 is about 74.9874349321.

Adding to 421663 its reverse (366124), we get a palindrome (787787).

The spelling of 421663 in words is "four hundred twenty-one thousand, six hundred sixty-three".