1685471985 has 24 divisors (see below), whose sum is σ = 2928265704. Its totient is φ = 896832000.

The previous prime is 1685471981. The next prime is 1685472011. The reversal of 1685471985 is 5891745861.

It is a happy number.

1685471985 is a `hidden beast` number, since 1 + 6 + 8 + 547 + 1 + 98 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 171950769 + 1513521216 = 13113^2 + 38904^2 .

It is not a de Polignac number, because 1685471985 - 2² = 1685471981 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1685471981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23766 + ... + 62735.

It is an arithmetic number, because the mean of its divisors is an integer number (122011071).

Almost surely, 2^1685471985 is an apocalyptic number.

1685471985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1685471985 is a deficient number, since it is larger than the sum of its proper divisors (1242793719).

1685471985 is a wasteful number, since it uses less digits than its factorization.

1685471985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86945 (or 86942 counting only the distinct ones).

The product of its digits is 2419200, while the sum is 54.

The square root of 1685471985 is about 41054.5001796393. The cubic root of 1685471985 is about 1190.0736684380.

The spelling of 1685471985 in words is "one billion, six hundred eighty-five million, four hundred seventy-one thousand, nine hundred eighty-five".