421491 has 8 divisors (see below), whose sum is σ = 642304. Its totient is φ = 240840.

The previous prime is 421483. The next prime is 421493. The reversal of 421491 is 194124.

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

It is not a de Polignac number, because 421491 - 2³ = 421483 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 20071 = 421491 / (4 + 2 + 1 + 4 + 9 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421493) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10015 + ... + 10056.

It is an arithmetic number, because the mean of its divisors is an integer number (80288).

2⁴²¹⁴⁹¹ is an apocalyptic number.

421491 is a deficient number, since it is larger than the sum of its proper divisors (220813).

421491 is a wasteful number, since it uses less digits than its factorization.

421491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20081.

The product of its digits is 288, while the sum is 21.

The square root of 421491 is about 649.2233822037. The cubic root of 421491 is about 74.9772375367.

The spelling of 421491 in words is "four hundred twenty-one thousand, four hundred ninety-one".