1821979323780 has 384 divisors, whose sum is σ = 7088956600320. Its totient is φ = 337568808960.

The previous prime is 1821979323779. The next prime is 1821979323793. The reversal of 1821979323780 is 873239791281.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 881784 + ... + 2102736.

It is an arithmetic number, because the mean of its divisors is an integer number (18460824480).

Almost surely, 2^{1821979323780} is an apocalyptic number.

1821979323780 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 1821979323780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3544478300160).

1821979323780 is an abundant number, since it is smaller than the sum of its proper divisors (5266977276540).

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

1821979323780 is a wasteful number, since it uses less digits than its factorization.

1821979323780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1221019 (or 1221017 counting only the distinct ones).

The product of its (nonzero) digits is 9144576, while the sum is 60.

The spelling of 1821979323780 in words is "one trillion, eight hundred twenty-one billion, nine hundred seventy-nine million, three hundred twenty-three thousand, seven hundred eighty".