1331820 has 108 divisors (see below), whose sum is σ = 4730544. Its totient is φ = 302400.

The previous prime is 1331801. The next prime is 1331821. The reversal of 1331820 is 281331.

It is a Harshad number since it is a multiple of its sum of digits (18).

1331820 is a Rhonda number in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 1331793 and 1331802.

It is not an unprimeable number, because it can be changed into a prime (1331821) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 8745 + ... + 8895.

2^1331820 is an apocalyptic number.

1331820 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 1331820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2365272).

1331820 is an abundant number, since it is smaller than the sum of its proper divisors (3398724).

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

1331820 is a wasteful number, since it uses less digits than its factorization.

1331820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 168 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 1331820 is about 1154.0450597789. The cubic root of 1331820 is about 110.0225848943.

It can be divided in two parts, 133 and 1820, that added together give a triangular number (1953 = T₆₂).

The spelling of 1331820 in words is "one million, three hundred thirty-one thousand, eight hundred twenty".