421524221 has 2 divisors, whose sum is σ = 421524222. Its totient is φ = 421524220.

The previous prime is 421524209. The next prime is 421524241. The reversal of 421524221 is 122425124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 234518596 + 187005625 = 15314^2 + 13675^2 .

It is a cyclic number.

It is not a de Polignac number, because 421524221 - 2¹⁸ = 421262077 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421524241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210762110 + 210762111.

It is an arithmetic number, because the mean of its divisors is an integer number (210762111).

Almost surely, 2^421524221 is an apocalyptic number.

It is an amenable number.

421524221 is a deficient number, since it is larger than the sum of its proper divisors (1).

421524221 is an equidigital number, since it uses as much as digits as its factorization.

421524221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1280, while the sum is 23.

The square root of 421524221 is about 20531.0550386482. The cubic root of 421524221 is about 749.7920733236.

Adding to 421524221 its reverse (122425124), we get a palindrome (543949345).

The spelling of 421524221 in words is "four hundred twenty-one million, five hundred twenty-four thousand, two hundred twenty-one".