1985817 has 4 divisors (see below), whose sum is σ = 2647760. Its totient is φ = 1323876.

The previous prime is 1985803. The next prime is 1985849. The reversal of 1985817 is 7185891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1985817 - 2⁷ = 1985689 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1985887) 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 in 3 ways as a sum of consecutive naturals, for example, 330967 + ... + 330972.

It is an arithmetic number, because the mean of its divisors is an integer number (661940).

2^1985817 is an apocalyptic number.

It is an amenable number.

1985817 is a deficient number, since it is larger than the sum of its proper divisors (661943).

1985817 is an equidigital number, since it uses as much as digits as its factorization.

1985817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661942.

The product of its digits is 20160, while the sum is 39.

The square root of 1985817 is about 1409.1901929832. The cubic root of 1985817 is about 125.6935738581.

The spelling of 1985817 in words is "one million, nine hundred eighty-five thousand, eight hundred seventeen".