421851 has 4 divisors (see below), whose sum is σ = 562472. Its totient is φ = 281232.

The previous prime is 421847. The next prime is 421891. The reversal of 421851 is 158124.

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

It is not a de Polignac number, because 421851 - 2² = 421847 is a prime.

It is a D-number.

It is the 650-th Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (421801) by changing a digit.

It is a nontrivial repunit in base 649.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70306 + ... + 70311.

It is an arithmetic number, because the mean of its divisors is an integer number (140618).

2⁴²¹⁸⁵¹ is an apocalyptic number.

421851 is a deficient number, since it is larger than the sum of its proper divisors (140621).

421851 is a wasteful number, since it uses less digits than its factorization.

421851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140620.

The product of its digits is 320, while the sum is 21.

The square root of 421851 is about 649.5005773669. The cubic root of 421851 is about 74.9985777508.

Adding to 421851 its reverse (158124), we get a palindrome (579975).

The spelling of 421851 in words is "four hundred twenty-one thousand, eight hundred fifty-one".