1856989 has 2 divisors, whose sum is σ = 1856990. Its totient is φ = 1856988.

The previous prime is 1856983. The next prime is 1856999. The reversal of 1856989 is 9896581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1734489 + 122500 = 1317^2 + 350^2 .

It is an emirp because it is prime and its reverse (9896581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1856989 - 2⁷ = 1856861 is a prime.

It is a super-2 number, since 2×1856989² = 6896816292242, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1856983) 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, 928494 + 928495.

It is an arithmetic number, because the mean of its divisors is an integer number (928495).

2^1856989 is an apocalyptic number.

It is an amenable number.

1856989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1856989 is an equidigital number, since it uses as much as digits as its factorization.

1856989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 46.

The square root of 1856989 is about 1362.7138364308. The cubic root of 1856989 is about 122.9144976093.

The spelling of 1856989 in words is "one million, eight hundred fifty-six thousand, nine hundred eighty-nine".