161982656821440 has 4032 divisors, whose sum is σ = 745231170797568. Its totient is φ = 31954806374400.

The previous prime is 161982656821439. The next prime is 161982656821459. The reversal of 161982656821440 is 44128656289161.

161982656821440 is a `hidden beast` number, since 1 + 6 + 1 + 9 + 8 + 2 + 6 + 568 + 21 + 4 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (4032).

It is a super-2 number, since 2×161982656821440² (a number of 29 digits) contains 22 as substring.

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

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 575 ways as a sum of consecutive naturals, for example, 296129171247 + ... + 296129171793.

It is an arithmetic number, because the mean of its divisors is an integer number (184829159424).

Almost surely, 2^{161982656821440} is an apocalyptic number.

161982656821440 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 161982656821440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (372615585398784).

161982656821440 is an abundant number, since it is smaller than the sum of its proper divisors (583248513976128).

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

161982656821440 is a wasteful number, since it uses less digits than its factorization.

161982656821440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796 (or 776 counting only the distinct ones).

The product of its (nonzero) digits is 39813120, while the sum is 63.

The spelling of 161982656821440 in words is "one hundred sixty-one trillion, nine hundred eighty-two billion, six hundred fifty-six million, eight hundred twenty-one thousand, four hundred forty".