1685505987 has 48 divisors (see below), whose sum is σ = 2934517248. Its totient is φ = 919607040.

The previous prime is 1685505971. The next prime is 1685505989. The reversal of 1685505987 is 7895055861.

1685505987 is a `hidden beast` number, since 1 + 6 + 8 + 550 + 5 + 9 + 87 = 666.

It is not a de Polignac number, because 1685505987 - 2⁴ = 1685505971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1685505989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16938 + ... + 60480.

It is an arithmetic number, because the mean of its divisors is an integer number (61135776).

Almost surely, 2^1685505987 is an apocalyptic number.

1685505987 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1685505987 is a deficient number, since it is larger than the sum of its proper divisors (1249011261).

1685505987 is a wasteful number, since it uses less digits than its factorization.

1685505987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43600 (or 43597 counting only the distinct ones).

The product of its (nonzero) digits is 3024000, while the sum is 54.

The square root of 1685505987 is about 41054.9142856248. The cubic root of 1685505987 is about 1190.0816710654.

The spelling of 1685505987 in words is "one billion, six hundred eighty-five million, five hundred five thousand, nine hundred eighty-seven".