1781921839104 has 768 divisors, whose sum is σ = 6126539328000. Its totient is φ = 505762283520.

The previous prime is 1781921839091. The next prime is 1781921839127. The reversal of 1781921839104 is 4019381291871.

1781921839104 is a `hidden beast` number, since 178 + 192 + 183 + 9 + 104 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4022396707 + ... + 4022397149.

It is an arithmetic number, because the mean of its divisors is an integer number (7977264750).

Almost surely, 2^{1781921839104} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1781921839104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3063269664000).

1781921839104 is an abundant number, since it is smaller than the sum of its proper divisors (4344617488896).

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

1781921839104 is a wasteful number, since it uses less digits than its factorization.

1781921839104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891 (or 865 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 54.

The spelling of 1781921839104 in words is "one trillion, seven hundred eighty-one billion, nine hundred twenty-one million, eight hundred thirty-nine thousand, one hundred four".