421344021 has 8 divisors (see below), whose sum is σ = 642048064. Its totient is φ = 240768000.

The previous prime is 421344013. The next prime is 421344089. The reversal of 421344021 is 120443124.

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

It is not a de Polignac number, because 421344021 - 2³ = 421344013 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: 20064001 = 421344021 / (4 + 2 + 1 + 3 + 4 + 4 + 0 + 2 + 1).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421344421) 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, 10031980 + ... + 10032021.

It is an arithmetic number, because the mean of its divisors is an integer number (80256008).

Almost surely, 2^421344021 is an apocalyptic number.

It is an amenable number.

421344021 is a deficient number, since it is larger than the sum of its proper divisors (220704043).

421344021 is a wasteful number, since it uses less digits than its factorization.

421344021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20064011.

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 421344021 is about 20526.6660955938. Note that the first 3 decimals coincide. The cubic root of 421344021 is about 749.6852136757.

Adding to 421344021 its reverse (120443124), we get a palindrome (541787145).

The spelling of 421344021 in words is "four hundred twenty-one million, three hundred forty-four thousand, twenty-one".