1381820 has 36 divisors (see below), whose sum is σ = 3195192. Its totient is φ = 501600.

The previous prime is 1381819. The next prime is 1381837. The reversal of 1381820 is 281831.

It is a nialpdrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2135 + ... + 2705.

2^1381820 is an apocalyptic number.

1381820 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 1381820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1597596).

1381820 is an abundant number, since it is smaller than the sum of its proper divisors (1813372).

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

1381820 is a wasteful number, since it uses less digits than its factorization.

1381820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602 (or 589 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 1381820 is about 1175.5084006505. The cubic root of 1381820 is about 111.3825504204.

The spelling of 1381820 in words is "one million, three hundred eighty-one thousand, eight hundred twenty".