1691680 has 48 divisors (see below), whose sum is σ = 4074840. Its totient is φ = 663552.

The previous prime is 1691659. The next prime is 1691681. The reversal of 1691680 is 861961.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1449616 + 242064 = 1204^2 + 492^2 .

It is not an unprimeable number, because it can be changed into a prime (1691681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15466 + ... + 15574.

2^1691680 is an apocalyptic number.

1691680 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 1691680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2037420).

1691680 is an abundant number, since it is smaller than the sum of its proper divisors (2383160).

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

1691680 is a wasteful number, since it uses less digits than its factorization.

1691680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 1691680 is about 1300.6459933433. The cubic root of 1691680 is about 119.1532991238.

It can be divided in two parts, 169 and 1680, that added together give a square (1849 = 43²).

The spelling of 1691680 in words is "one million, six hundred ninety-one thousand, six hundred eighty".