421131209 has 2 divisors, whose sum is σ = 421131210. Its totient is φ = 421131208.

The previous prime is 421131167. The next prime is 421131253. The reversal of 421131209 is 902131124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 290532025 + 130599184 = 17045^2 + 11428^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421131209 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (421151209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210565604 + 210565605.

It is an arithmetic number, because the mean of its divisors is an integer number (210565605).

Almost surely, 2^421131209 is an apocalyptic number.

It is an amenable number.

421131209 is a deficient number, since it is larger than the sum of its proper divisors (1).

421131209 is an equidigital number, since it uses as much as digits as its factorization.

421131209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 421131209 is about 20521.4816472885. The cubic root of 421131209 is about 749.5589756772.

The spelling of 421131209 in words is "four hundred twenty-one million, one hundred thirty-one thousand, two hundred nine".