406431391 has 2 divisors, whose sum is σ = 406431392. Its totient is φ = 406431390.

The previous prime is 406431331. The next prime is 406431397. The reversal of 406431391 is 193134604.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 406431391 - 2⁹ = 406430879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (406431397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203215695 + 203215696.

It is an arithmetic number, because the mean of its divisors is an integer number (203215696).

Almost surely, 2^406431391 is an apocalyptic number.

406431391 is a deficient number, since it is larger than the sum of its proper divisors (1).

406431391 is an equidigital number, since it uses as much as digits as its factorization.

406431391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 406431391 is about 20160.1436254804. The cubic root of 406431391 is about 740.7342304691.

Adding to 406431391 its reverse (193134604), we get a palindrome (599565995).

The spelling of 406431391 in words is "four hundred six million, four hundred thirty-one thousand, three hundred ninety-one".