421561 has 4 divisors (see below), whose sum is σ = 481792. Its totient is φ = 361332.

The previous prime is 421559. The next prime is 421607. The reversal of 421561 is 165124.

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 421561 - 2¹ = 421559 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (421501) 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, 30105 + ... + 30118.

It is an arithmetic number, because the mean of its divisors is an integer number (120448).

2⁴²¹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

421561 is a deficient number, since it is larger than the sum of its proper divisors (60231).

421561 is an equidigital number, since it uses as much as digits as its factorization.

421561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60230.

The product of its digits is 240, while the sum is 19.

The square root of 421561 is about 649.2772905316. The cubic root of 421561 is about 74.9813879742.

Adding to 421561 its reverse (165124), we get a palindrome (586685).

The spelling of 421561 in words is "four hundred twenty-one thousand, five hundred sixty-one".