168521540 has 72 divisors (see below), whose sum is σ = 394148160. Its totient is φ = 60470080.

The previous prime is 168521539. The next prime is 168521543. The reversal of 168521540 is 45125861.

It is a junction number, because it is equal to n+sod(n) for n = 168521497 and 168521506.

It is not an unprimeable number, because it can be changed into a prime (168521543) 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 23 ways as a sum of consecutive naturals, for example, 200441 + ... + 201279.

It is an arithmetic number, because the mean of its divisors is an integer number (5474280).

Almost surely, 2^168521540 is an apocalyptic number.

168521540 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 168521540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197074080).

168521540 is an abundant number, since it is smaller than the sum of its proper divisors (225626620).

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

168521540 is a wasteful number, since it uses less digits than its factorization.

168521540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 953 (or 940 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 168521540 is about 12981.5846490326. The cubic root of 168521540 is about 552.3552332574.

The spelling of 168521540 in words is "one hundred sixty-eight million, five hundred twenty-one thousand, five hundred forty".