165781219968 has 1280 divisors, whose sum is σ = 644430124800. Its totient is φ = 41134915584.

The previous prime is 165781219963. The next prime is 165781219969. The reversal of 165781219968 is 869912187561.

It is a Harshad number since it is a multiple of its sum of digits (63).

Its product of digits (13063680) is a multiple of the sum of its prime divisors (210).

It is not an unprimeable number, because it can be changed into a prime (165781219963) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1997364055 + ... + 1997364137.

It is an arithmetic number, because the mean of its divisors is an integer number (503461035).

Almost surely, 2^165781219968 is an apocalyptic number.

165781219968 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 165781219968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (322215062400).

165781219968 is an abundant number, since it is smaller than the sum of its proper divisors (478648904832).

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

165781219968 is a wasteful number, since it uses less digits than its factorization.

165781219968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231 (or 210 counting only the distinct ones).

The product of its digits is 13063680, while the sum is 63.

The spelling of 165781219968 in words is "one hundred sixty-five billion, seven hundred eighty-one million, two hundred nineteen thousand, nine hundred sixty-eight".