165868640 has 192 divisors, whose sum is σ = 480743424. Its totient is φ = 52850688.

The previous prime is 165868627. The next prime is 165868691. The reversal of 165868640 is 46868561.

It is a Cunningham number, because it is equal to 12879²-1.

It is a junction number, because it is equal to n+sod(n) for n = 165868591 and 165868600.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 1210652 + ... + 1210788.

It is an arithmetic number, because the mean of its divisors is an integer number (2503872).

Almost surely, 2^165868640 is an apocalyptic number.

165868640 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 165868640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (240371712).

165868640 is an abundant number, since it is smaller than the sum of its proper divisors (314874784).

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

165868640 is a wasteful number, since it uses less digits than its factorization.

165868640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 44.

The square root of 165868640 is about 12878.9999611771. Note that the first 4 decimals coincide. The cubic root of 165868640 is about 549.4414605287.

The spelling of 165868640 in words is "one hundred sixty-five million, eight hundred sixty-eight thousand, six hundred forty".