1668820 has 24 divisors (see below), whose sum is σ = 3531528. Its totient is φ = 662400.

The previous prime is 1668803. The next prime is 1668833. The reversal of 1668820 is 288661.

It can be written as a sum of positive squares in 4 ways, for example, as 20164 + 1648656 = 142^2 + 1284^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3390 + ... + 3850.

It is an arithmetic number, because the mean of its divisors is an integer number (147147).

2^1668820 is an apocalyptic number.

1668820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1668820 is an abundant number, since it is smaller than the sum of its proper divisors (1862708).

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

1668820 is a wasteful number, since it uses less digits than its factorization.

1668820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651 (or 649 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 1668820 is about 1291.8281619472. The cubic root of 1668820 is about 118.6141493545.

The spelling of 1668820 in words is "one million, six hundred sixty-eight thousand, eight hundred twenty".