421865 has 8 divisors (see below), whose sum is σ = 510720. Its totient is φ = 334512.

The previous prime is 421847. The next prime is 421891. The reversal of 421865 is 568124.

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

It is a cyclic number.

It is not a de Polignac number, because 421865 - 2⁶ = 421801 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 392 + ... + 998.

It is an arithmetic number, because the mean of its divisors is an integer number (63840).

2⁴²¹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

421865 is a deficient number, since it is larger than the sum of its proper divisors (88855).

421865 is a wasteful number, since it uses less digits than its factorization.

421865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751.

The product of its digits is 1920, while the sum is 26.

The square root of 421865 is about 649.5113547891. The cubic root of 421865 is about 74.9994074027. Note that the first 3 decimals are identical.

Adding to 421865 its reverse (568124), we get a palindrome (989989).

It can be divided in two parts, 4218 and 65, that multiplied together give a triangular number (274170 = T₇₄₀).

The spelling of 421865 in words is "four hundred twenty-one thousand, eight hundred sixty-five".