1685120665 has 16 divisors (see below), whose sum is σ = 2142327312. Its totient is φ = 1268066304.

The previous prime is 1685120629. The next prime is 1685120683. The reversal of 1685120665 is 5660215861.

It can be written as a sum of positive squares in 8 ways, for example, as 2152089 + 1682968576 = 1467^2 + 41024^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685120665 - 2⁹ = 1685120153 is a prime.

It is a super-2 number, since 2×1685120665² = 5679263311220084450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 177007 + ... + 186283.

It is an arithmetic number, because the mean of its divisors is an integer number (133895457).

Almost surely, 2^1685120665 is an apocalyptic number.

It is an amenable number.

1685120665 is a deficient number, since it is larger than the sum of its proper divisors (457206647).

1685120665 is a wasteful number, since it uses less digits than its factorization.

1685120665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11436.

The product of its (nonzero) digits is 86400, while the sum is 40.

The square root of 1685120665 is about 41050.2212539713. The cubic root of 1685120665 is about 1189.9909763221.

The spelling of 1685120665 in words is "one billion, six hundred eighty-five million, one hundred twenty thousand, six hundred sixty-five".