42421 has 4 divisors (see below), whose sum is σ = 43200. Its totient is φ = 41644.

The previous prime is 42409. The next prime is 42433. The reversal of 42421 is 12424.

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 an interprime number because it is at equal distance from previous prime (42409) and next prime (42433).

It is a cyclic number.

It is not a de Polignac number, because 42421 - 2⁷ = 42293 is a prime.

It is a Duffinian number.

42421 is a lucky number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42451) 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, 301 + ... + 418.

It is an arithmetic number, because the mean of its divisors is an integer number (10800).

2⁴²⁴²¹ is an apocalyptic number.

It is an amenable number.

42421 is a deficient number, since it is larger than the sum of its proper divisors (779).

42421 is an equidigital number, since it uses as much as digits as its factorization.

42421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778.

The product of its digits is 64, while the sum is 13.

The square root of 42421 is about 205.9635890151. The cubic root of 42421 is about 34.8760239590.

Adding to 42421 its reverse (12424), we get a palindrome (54845).

The spelling of 42421 in words is "forty-two thousand, four hundred twenty-one", and thus it is an iban number.