1906391 has 2 divisors, whose sum is σ = 1906392. Its totient is φ = 1906390.

The previous prime is 1906381. The next prime is 1906393. The reversal of 1906391 is 1936091.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1906391 - 2¹⁰ = 1905367 is a prime.

Together with 1906393, 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 (1906393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 953195 + 953196.

It is an arithmetic number, because the mean of its divisors is an integer number (953196).

2^1906391 is an apocalyptic number.

1906391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1906391 is an equidigital number, since it uses as much as digits as its factorization.

1906391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 29.

The square root of 1906391 is about 1380.7211883650. The cubic root of 1906391 is about 123.9949486322.

The spelling of 1906391 in words is "one million, nine hundred six thousand, three hundred ninety-one".