1686720 has 112 divisors (see below), whose sum is σ = 6144768. Its totient is φ = 384000.

The previous prime is 1686703. The next prime is 1686743. The reversal of 1686720 is 276861.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6595 + ... + 6845.

It is an arithmetic number, because the mean of its divisors is an integer number (54864).

2^1686720 is an apocalyptic number.

1686720 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 1686720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3072384).

1686720 is an abundant number, since it is smaller than the sum of its proper divisors (4458048).

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

1686720 is a wasteful number, since it uses less digits than its factorization.

1686720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 1686720 is about 1298.7378488363. The cubic root of 1686720 is about 119.0367327696.

It can be divided in two parts, 16 and 86720, that added together give a triangular number (86736 = T₄₁₆).

The spelling of 1686720 in words is "one million, six hundred eighty-six thousand, seven hundred twenty".