409400491 has 2 divisors, whose sum is σ = 409400492. Its totient is φ = 409400490.

The previous prime is 409400489. The next prime is 409400603. The reversal of 409400491 is 194004904.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 409400491 - 2¹ = 409400489 is a prime.

Together with 409400489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (409400441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204700245 + 204700246.

It is an arithmetic number, because the mean of its divisors is an integer number (204700246).

Almost surely, 2^409400491 is an apocalyptic number.

409400491 is a deficient number, since it is larger than the sum of its proper divisors (1).

409400491 is an equidigital number, since it uses as much as digits as its factorization.

409400491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 409400491 is about 20233.6474961881. The cubic root of 409400491 is about 742.5336158338.

The spelling of 409400491 in words is "four hundred nine million, four hundred thousand, four hundred ninety-one".