1681216 has 28 divisors (see below), whose sum is σ = 3380740. Its totient is φ = 829440.

The previous prime is 1681201. The next prime is 1681219. The reversal of 1681216 is 6121861.

It can be written as a sum of positive squares in 2 ways, for example, as 1218816 + 462400 = 1104^2 + 680^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6856 + ... + 7096.

2^1681216 is an apocalyptic number.

1681216 is a gapful number since it is divisible by the number (16) 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 1681216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1690370).

1681216 is an abundant number, since it is smaller than the sum of its proper divisors (1699524).

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

1681216 is a wasteful number, since it uses less digits than its factorization.

1681216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362 (or 352 counting only the distinct ones).

The product of its digits is 576, while the sum is 25.

The square root of 1681216 is about 1296.6171370146. The cubic root of 1681216 is about 118.9071139201.

The spelling of 1681216 in words is "one million, six hundred eighty-one thousand, two hundred sixteen".