381391709 has 2 divisors, whose sum is σ = 381391710. Its totient is φ = 381391708.

The previous prime is 381391691. The next prime is 381391711. The reversal of 381391709 is 907193183.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 362712025 + 18679684 = 19045^2 + 4322^2 .

It is a cyclic number.

It is not a de Polignac number, because 381391709 - 2²⁰ = 380343133 is a prime.

Together with 381391711, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (381391609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 190695854 + 190695855.

It is an arithmetic number, because the mean of its divisors is an integer number (190695855).

Almost surely, 2^381391709 is an apocalyptic number.

It is an amenable number.

381391709 is a deficient number, since it is larger than the sum of its proper divisors (1).

381391709 is an equidigital number, since it uses as much as digits as its factorization.

381391709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 381391709 is about 19529.2526482710. The cubic root of 381391709 is about 725.1988096866.

The spelling of 381391709 in words is "three hundred eighty-one million, three hundred ninety-one thousand, seven hundred nine".