1820780881920 has 4608 divisors, whose sum is σ = 9519869399040. Its totient is φ = 321052999680.

The previous prime is 1820780881901. The next prime is 1820780881943. The reversal of 1820780881920 is 291880870281.

It is a tau number, because it is divible by the number of its divisors (4608).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 42343741419 + ... + 42343741461.

It is an arithmetic number, because the mean of its divisors is an integer number (2065943880).

Almost surely, 2^{1820780881920} is an apocalyptic number.

1820780881920 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 1820780881920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4759934699520).

1820780881920 is an abundant number, since it is smaller than the sum of its proper divisors (7699088517120).

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

1820780881920 is a wasteful number, since it uses less digits than its factorization.

1820780881920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 54.

The spelling of 1820780881920 in words is "one trillion, eight hundred twenty billion, seven hundred eighty million, eight hundred eighty-one thousand, nine hundred twenty".