1861859 has 2 divisors, whose sum is σ = 1861860. Its totient is φ = 1861858.

The previous prime is 1861831. The next prime is 1861861. The reversal of 1861859 is 9581681.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1861859 - 2²⁰ = 813283 is a prime.

It is a Sophie Germain prime.

Together with 1861861, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1861879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930929 + 930930.

It is an arithmetic number, because the mean of its divisors is an integer number (930930).

2^1861859 is an apocalyptic number.

1861859 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861859 is an equidigital number, since it uses as much as digits as its factorization.

1861859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 38.

The square root of 1861859 is about 1364.4995419567. The cubic root of 1861859 is about 123.0218525961.

The spelling of 1861859 in words is "one million, eight hundred sixty-one thousand, eight hundred fifty-nine".