165513220 has 24 divisors (see below), whose sum is σ = 347899608. Its totient is φ = 66144000.

The previous prime is 165513209. The next prime is 165513239. The reversal of 165513220 is 22315561.

It can be written as a sum of positive squares in 4 ways, for example, as 5541316 + 159971904 = 2354^2 + 12648^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22840 + ... + 29200.

It is an arithmetic number, because the mean of its divisors is an integer number (14495817).

Almost surely, 2^165513220 is an apocalyptic number.

165513220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165513220 is an abundant number, since it is smaller than the sum of its proper divisors (182386388).

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

165513220 is a wasteful number, since it uses less digits than its factorization.

165513220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7671 (or 7669 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 165513220 is about 12865.1941298995. The cubic root of 165513220 is about 549.0487358347.

Adding to 165513220 its reverse (22315561), we get a palindrome (187828781).

The spelling of 165513220 in words is "one hundred sixty-five million, five hundred thirteen thousand, two hundred twenty".