165539840 has 104 divisors (see below), whose sum is σ = 406928880. Its totient is φ = 64618496.

The previous prime is 165539833. The next prime is 165539851. The reversal of 165539840 is 48935561.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1208252 + ... + 1208388.

Almost surely, 2^165539840 is an apocalyptic number.

165539840 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 165539840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (203464440).

165539840 is an abundant number, since it is smaller than the sum of its proper divisors (241389040).

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

165539840 is an equidigital number, since it uses as much as digits as its factorization.

165539840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 41.

The square root of 165539840 is about 12866.2286626657. The cubic root of 165539840 is about 549.0781693222.

The spelling of 165539840 in words is "one hundred sixty-five million, five hundred thirty-nine thousand, eight hundred forty".