1821126779680 has 192 divisors, whose sum is σ = 4666050385920. Its totient is φ = 667689947136.

The previous prime is 1821126779609. The next prime is 1821126779687. The reversal of 1821126779680 is 869776211281.

It is a hoax number, since the sum of its digits (58) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1821126779687) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 172466241 + ... + 172476799.

It is an arithmetic number, because the mean of its divisors is an integer number (24302345760).

Almost surely, 2^{1821126779680} is an apocalyptic number.

1821126779680 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 1821126779680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2333025192960).

1821126779680 is an abundant number, since it is smaller than the sum of its proper divisors (2844923606240).

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

1821126779680 is a wasteful number, since it uses less digits than its factorization.

1821126779680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11163 (or 11155 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 58.

The spelling of 1821126779680 in words is "one trillion, eight hundred twenty-one billion, one hundred twenty-six million, seven hundred seventy-nine thousand, six hundred eighty".