421909 has 4 divisors (see below), whose sum is σ = 429120. Its totient is φ = 414700.

The previous prime is 421907. The next prime is 421913. The reversal of 421909 is 909124.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 421909 - 2¹ = 421907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3517 + ... + 3634.

It is an arithmetic number, because the mean of its divisors is an integer number (107280).

2⁴²¹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

421909 is a deficient number, since it is larger than the sum of its proper divisors (7211).

421909 is an equidigital number, since it uses as much as digits as its factorization.

421909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7210.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 421909 is about 649.5452255232. The cubic root of 421909 is about 75.0020147607.

The spelling of 421909 in words is "four hundred twenty-one thousand, nine hundred nine".