165820640 has 48 divisors (see below), whose sum is σ = 393407280. Its totient is φ = 66048000.

The previous prime is 165820597. The next prime is 165820649. The reversal of 165820640 is 46028561.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 165820597 and 165820606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165820649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38096 + ... + 42224.

It is an arithmetic number, because the mean of its divisors is an integer number (8195985).

Almost surely, 2^165820640 is an apocalyptic number.

165820640 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 165820640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (196703640).

165820640 is an abundant number, since it is smaller than the sum of its proper divisors (227586640).

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

165820640 is a wasteful number, since it uses less digits than its factorization.

165820640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4395 (or 4387 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 165820640 is about 12877.1363276157. The cubic root of 165820640 is about 549.3884552619.

The spelling of 165820640 in words is "one hundred sixty-five million, eight hundred twenty thousand, six hundred forty".