1691885685 has 64 divisors (see below), whose sum is σ = 3264030720. Its totient is φ = 731047680.

The previous prime is 1691885579. The next prime is 1691885693. The reversal of 1691885685 is 5865881961.

It is a happy number.

It is not a de Polignac number, because 1691885685 - 2²⁵ = 1658331253 is a prime.

It is a super-2 number, since 2×1691885685² = 5724954342215838450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1318054 + ... + 1319336.

It is an arithmetic number, because the mean of its divisors is an integer number (51000480).

Almost surely, 2^1691885685 is an apocalyptic number.

1691885685 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1691885685 is a deficient number, since it is larger than the sum of its proper divisors (1572145035).

1691885685 is a wasteful number, since it uses less digits than its factorization.

1691885685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1978.

The product of its digits is 4147200, while the sum is 57.

The square root of 1691885685 is about 41132.5380325601. The cubic root of 1691885685 is about 1191.5812806170.

The spelling of 1691885685 in words is "one billion, six hundred ninety-one million, eight hundred eighty-five thousand, six hundred eighty-five".