1686420 has 72 divisors (see below), whose sum is σ = 5320224. Its totient is φ = 448416.

The previous prime is 1686409. The next prime is 1686439. The reversal of 1686420 is 246861.

1686420 is a `hidden beast` number, since 16 + 8 + 642 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4687 + ... + 5033.

It is an arithmetic number, because the mean of its divisors is an integer number (73892).

2^1686420 is an apocalyptic number.

1686420 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 1686420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2660112).

1686420 is an abundant number, since it is smaller than the sum of its proper divisors (3633804).

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

1686420 is a wasteful number, since it uses less digits than its factorization.

1686420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371 (or 357 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1686420 is about 1298.6223469508. The cubic root of 1686420 is about 119.0296750605.

It can be divided in two parts, 16 and 86420, that added together give a square (86436 = 294²).

The spelling of 1686420 in words is "one million, six hundred eighty-six thousand, four hundred twenty".