421312021 has 4 divisors (see below), whose sum is σ = 453720652. Its totient is φ = 388903392.

The previous prime is 421312019. The next prime is 421312033. The reversal of 421312021 is 120213124.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45495025 + 375816996 = 6745^2 + 19386^2 .

It is a cyclic number.

It is not a de Polignac number, because 421312021 - 2¹ = 421312019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 421311986 and 421312004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421312621) 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, 16204296 + ... + 16204321.

It is an arithmetic number, because the mean of its divisors is an integer number (113430163).

Almost surely, 2^421312021 is an apocalyptic number.

It is an amenable number.

421312021 is a deficient number, since it is larger than the sum of its proper divisors (32408631).

421312021 is a wasteful number, since it uses less digits than its factorization.

421312021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32408630.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 421312021 is about 20525.8866069166. The cubic root of 421312021 is about 749.6662343041. Note that the first 3 decimals are identical.

Adding to 421312021 its reverse (120213124), we get a palindrome (541525145).

The spelling of 421312021 in words is "four hundred twenty-one million, three hundred twelve thousand, twenty-one".