408378391 has 2 divisors, whose sum is σ = 408378392. Its totient is φ = 408378390.

The previous prime is 408378379. The next prime is 408378427. The reversal of 408378391 is 193873804.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 408378391 - 2⁷ = 408378263 is a prime.

It is a super-3 number, since 3×408378391³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (408378331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204189195 + 204189196.

It is an arithmetic number, because the mean of its divisors is an integer number (204189196).

Almost surely, 2^408378391 is an apocalyptic number.

408378391 is a deficient number, since it is larger than the sum of its proper divisors (1).

408378391 is an equidigital number, since it uses as much as digits as its factorization.

408378391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 408378391 is about 20208.3742789963. The cubic root of 408378391 is about 741.9151700087.

The spelling of 408378391 in words is "four hundred eight million, three hundred seventy-eight thousand, three hundred ninety-one".