1688644860 has 144 divisors (see below), whose sum is σ = 5634709920. Its totient is φ = 376535040.

The previous prime is 1688644847. The next prime is 1688644879. The reversal of 1688644860 is 684468861.

It is a congruent number.

It is an unprimeable number.

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, 113536 + ... + 127544.

It is an arithmetic number, because the mean of its divisors is an integer number (39129930).

Almost surely, 2^1688644860 is an apocalyptic number.

1688644860 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1688644860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2817354960).

1688644860 is an abundant number, since it is smaller than the sum of its proper divisors (3946065060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1688644860 is a wasteful number, since it uses less digits than its factorization.

1688644860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14076 (or 14067 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 51.

The square root of 1688644860 is about 41093.1242423839. The cubic root of 1688644860 is about 1190.8199654410.

The spelling of 1688644860 in words is "one billion, six hundred eighty-eight million, six hundred forty-four thousand, eight hundred sixty".