1781663331168 has 768 divisors, whose sum is σ = 6489310464000. Its totient is φ = 465310863360.

The previous prime is 1781663331127. The next prime is 1781663331223. The reversal of 1781663331168 is 8611333661871.

1781663331168 is a `hidden beast` number, since 17 + 81 + 6 + 63 + 331 + 168 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1203012988 + ... + 1203014468.

It is an arithmetic number, because the mean of its divisors is an integer number (8449623000).

Almost surely, 2^{1781663331168} is an apocalyptic number.

1781663331168 is a gapful number since it is divisible by the number (18) 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 1781663331168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3244655232000).

1781663331168 is an abundant number, since it is smaller than the sum of its proper divisors (4707647132832).

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

1781663331168 is a wasteful number, since it uses less digits than its factorization.

1781663331168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593 (or 1541 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 1781663331168 in words is "one trillion, seven hundred eighty-one billion, six hundred sixty-three million, three hundred thirty-one thousand, one hundred sixty-eight".