1997785 has 4 divisors (see below), whose sum is σ = 2397348. Its totient is φ = 1598224.

The previous prime is 1997773. The next prime is 1997813. The reversal of 1997785 is 5877991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 506944 + 1490841 = 712^2 + 1221^2 .

It is a cyclic number.

It is not a de Polignac number, because 1997785 - 2⁵ = 1997753 is a prime.

It is a super-2 number, since 2×1997785² = 7982289812450, which contains 22 as substring.

It is a Duffinian number.

1997785 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199774 + ... + 199783.

It is an arithmetic number, because the mean of its divisors is an integer number (599337).

2^1997785 is an apocalyptic number.

It is an amenable number.

1997785 is a deficient number, since it is larger than the sum of its proper divisors (399563).

1997785 is an equidigital number, since it uses as much as digits as its factorization.

1997785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399562.

The product of its digits is 158760, while the sum is 46.

The square root of 1997785 is about 1413.4302246662. The cubic root of 1997785 is about 125.9455757228.

The spelling of 1997785 in words is "one million, nine hundred ninety-seven thousand, seven hundred eighty-five".