165444981840 has 400 divisors, whose sum is σ = 602554398336. Its totient is φ = 41992473600.

The previous prime is 165444981811. The next prime is 165444981847. The reversal of 165444981840 is 48189444561.

165444981840 is a `hidden beast` number, since 1 + 6 + 544 + 4 + 98 + 1 + 8 + 4 + 0 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165444981847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 31444810 + ... + 31450070.

Almost surely, 2^165444981840 is an apocalyptic number.

165444981840 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 165444981840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301277199168).

165444981840 is an abundant number, since it is smaller than the sum of its proper divisors (437109416496).

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

165444981840 is a wasteful number, since it uses less digits than its factorization.

165444981840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5520 (or 5505 counting only the distinct ones).

The product of its (nonzero) digits is 4423680, while the sum is 54.

The spelling of 165444981840 in words is "one hundred sixty-five billion, four hundred forty-four million, nine hundred eighty-one thousand, eight hundred forty".