1851391 has 2 divisors, whose sum is σ = 1851392. Its totient is φ = 1851390.

The previous prime is 1851373. The next prime is 1851401. The reversal of 1851391 is 1931581.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1851391 - 2⁵ = 1851359 is a prime.

It is a Chen prime.

1851391 is a lucky number.

It is a zygodrome in base 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1851301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 925695 + 925696.

It is an arithmetic number, because the mean of its divisors is an integer number (925696).

2^1851391 is an apocalyptic number.

1851391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1851391 is an equidigital number, since it uses as much as digits as its factorization.

1851391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 28.

The square root of 1851391 is about 1360.6582965609. The cubic root of 1851391 is about 122.7908623531.

The spelling of 1851391 in words is "one million, eight hundred fifty-one thousand, three hundred ninety-one".