1909381 has 2 divisors, whose sum is σ = 1909382. Its totient is φ = 1909380.

The previous prime is 1909373. The next prime is 1909399. The reversal of 1909381 is 1839091.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1846881 + 62500 = 1359^2 + 250^2 .

It is an emirp because it is prime and its reverse (1839091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1909381 - 2³ = 1909373 is a prime.

It is a super-2 number, since 2×1909381² = 7291471606322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1909081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954690 + 954691.

It is an arithmetic number, because the mean of its divisors is an integer number (954691).

2^1909381 is an apocalyptic number.

It is an amenable number.

1909381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909381 is an equidigital number, since it uses as much as digits as its factorization.

1909381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 1909381 is about 1381.8035316209. The cubic root of 1909381 is about 124.0597396848.

The spelling of 1909381 in words is "one million, nine hundred nine thousand, three hundred eighty-one".