421681 has 8 divisors (see below), whose sum is σ = 459200. Its totient is φ = 384912.

The previous prime is 421661. The next prime is 421691. The reversal of 421681 is 186124.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421681 is a prime.

It is a super-2 number, since 2×421681² = 355629731522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (421621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2020 + ... + 2218.

It is an arithmetic number, because the mean of its divisors is an integer number (57400).

2⁴²¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

421681 is a deficient number, since it is larger than the sum of its proper divisors (37519).

421681 is a wasteful number, since it uses less digits than its factorization.

421681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375.

The product of its digits is 384, while the sum is 22.

The square root of 421681 is about 649.3696943960. The cubic root of 421681 is about 74.9885019411.

The spelling of 421681 in words is "four hundred twenty-one thousand, six hundred eighty-one".