1861543 has 2 divisors, whose sum is σ = 1861544. Its totient is φ = 1861542.

The previous prime is 1861511. The next prime is 1861547. The reversal of 1861543 is 3451681.

It is a strong prime.

It is an emirp because it is prime and its reverse (3451681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1861543 - 2⁵ = 1861511 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1861547) 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, 930771 + 930772.

It is an arithmetic number, because the mean of its divisors is an integer number (930772).

2^1861543 is an apocalyptic number.

1861543 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861543 is an equidigital number, since it uses as much as digits as its factorization.

1861543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 28.

The square root of 1861543 is about 1364.3837436733. The cubic root of 1861543 is about 123.0148923295.

The spelling of 1861543 in words is "one million, eight hundred sixty-one thousand, five hundred forty-three".