421340209 has 2 divisors, whose sum is σ = 421340210. Its totient is φ = 421340208.

The previous prime is 421340207. The next prime is 421340221. The reversal of 421340209 is 902043124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 369715984 + 51624225 = 19228^2 + 7185^2 .

It is a cyclic number.

It is not a de Polignac number, because 421340209 - 2¹ = 421340207 is a prime.

Together with 421340207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (421340207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210670104 + 210670105.

It is an arithmetic number, because the mean of its divisors is an integer number (210670105).

Almost surely, 2^421340209 is an apocalyptic number.

It is an amenable number.

421340209 is a deficient number, since it is larger than the sum of its proper divisors (1).

421340209 is an equidigital number, since it uses as much as digits as its factorization.

421340209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 421340209 is about 20526.5732405582. The cubic root of 421340209 is about 749.6829528085.

The spelling of 421340209 in words is "four hundred twenty-one million, three hundred forty thousand, two hundred nine".