168921807840 has 144 divisors (see below), whose sum is σ = 577458017136. Its totient is φ = 44966707200.

The previous prime is 168921807839. The next prime is 168921807869. The reversal of 168921807840 is 48708129861.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 719520 + ... + 924960.

It is an arithmetic number, because the mean of its divisors is an integer number (4010125119).

Almost surely, 2^168921807840 is an apocalyptic number.

168921807840 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 168921807840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (288729008568).

168921807840 is an abundant number, since it is smaller than the sum of its proper divisors (408536209296).

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

168921807840 is a wasteful number, since it uses less digits than its factorization.

168921807840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206033 (or 206022 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 168921807840 in words is "one hundred sixty-eight billion, nine hundred twenty-one million, eight hundred seven thousand, eight hundred forty".