165917820 has 24 divisors (see below), whose sum is σ = 464570064. Its totient is φ = 44244736.

The previous prime is 165917809. The next prime is 165917827. The reversal of 165917820 is 28719561.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165917827) 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, 1382589 + ... + 1382708.

It is an arithmetic number, because the mean of its divisors is an integer number (19357086).

Almost surely, 2^165917820 is an apocalyptic number.

165917820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165917820 is an abundant number, since it is smaller than the sum of its proper divisors (298652244).

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

165917820 is a wasteful number, since it uses less digits than its factorization.

165917820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2765309 (or 2765307 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 39.

The square root of 165917820 is about 12880.9091294054. The cubic root of 165917820 is about 549.4957582365.

The spelling of 165917820 in words is "one hundred sixty-five million, nine hundred seventeen thousand, eight hundred twenty".