1686039840 has 384 divisors, whose sum is σ = 6270566400. Its totient is φ = 422231040.

The previous prime is 1686039827. The next prime is 1686039851. The reversal of 1686039840 is 489306861.

1686039840 is a `hidden beast` number, since 168 + 60 + 398 + 40 = 666.

1686039840 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×1686039840³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7054441 + ... + 7054679.

It is an arithmetic number, because the mean of its divisors is an integer number (16329600).

Almost surely, 2^1686039840 is an apocalyptic number.

1686039840 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 1686039840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3135283200).

1686039840 is an abundant number, since it is smaller than the sum of its proper divisors (4584526560).

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

1686039840 is a wasteful number, since it uses less digits than its factorization.

1686039840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357 (or 343 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 1686039840 is about 41061.4154651298. The cubic root of 1686039840 is about 1190.2073032911.

The spelling of 1686039840 in words is "one billion, six hundred eighty-six million, thirty-nine thousand, eight hundred forty".