431421209 has 2 divisors, whose sum is σ = 431421210. Its totient is φ = 431421208.

The previous prime is 431421191. The next prime is 431421217. The reversal of 431421209 is 902124134.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 314175625 + 117245584 = 17725^2 + 10828^2 .

It is a cyclic number.

It is not a de Polignac number, because 431421209 - 2¹² = 431417113 is a prime.

It is a super-2 number, since 2×431421209² = 372248519150043362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (431421259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 215710604 + 215710605.

It is an arithmetic number, because the mean of its divisors is an integer number (215710605).

Almost surely, 2^431421209 is an apocalyptic number.

It is an amenable number.

431421209 is a deficient number, since it is larger than the sum of its proper divisors (1).

431421209 is an equidigital number, since it uses as much as digits as its factorization.

431421209 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 26.

The square root of 431421209 is about 20770.6814765428. The cubic root of 431421209 is about 755.6148721221.

The spelling of 431421209 in words is "four hundred thirty-one million, four hundred twenty-one thousand, two hundred nine".