421224021 has 24 divisors (see below), whose sum is σ = 628148664. Its totient is φ = 271797120.

The previous prime is 421224017. The next prime is 421224061. The reversal of 421224021 is 120422124.

421224021 is a `hidden beast` number, since 421 + 2 + 240 + 2 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 227708100 + 193515921 = 15090^2 + 13911^2 .

It is not a de Polignac number, because 421224021 - 2² = 421224017 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 421223985 and 421224003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421224061) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62391 + ... + 68811.

It is an arithmetic number, because the mean of its divisors is an integer number (26172861).

Almost surely, 2^421224021 is an apocalyptic number.

It is an amenable number.

421224021 is a deficient number, since it is larger than the sum of its proper divisors (206924643).

421224021 is a wasteful number, since it uses less digits than its factorization.

421224021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6661 (or 6658 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 421224021 is about 20523.7428604044. The cubic root of 421224021 is about 749.6140360765.

Adding to 421224021 its reverse (120422124), we get a palindrome (541646145).

The spelling of 421224021 in words is "four hundred twenty-one million, two hundred twenty-four thousand, twenty-one".