165641540 has 48 divisors (see below), whose sum is σ = 370328112. Its totient is φ = 62017536.

The previous prime is 165641537. The next prime is 165641551. The reversal of 165641540 is 45146561.

It can be written as a sum of positive squares in 8 ways, for example, as 41809156 + 123832384 = 6466^2 + 11128^2 .

It is a junction number, because it is equal to n+sod(n) for n = 165641497 and 165641506.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65744 + ... + 68216.

It is an arithmetic number, because the mean of its divisors is an integer number (7715169).

Almost surely, 2^165641540 is an apocalyptic number.

165641540 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 165641540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (185164056).

165641540 is an abundant number, since it is smaller than the sum of its proper divisors (204686572).

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

165641540 is a wasteful number, since it uses less digits than its factorization.

165641540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696 (or 2694 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 32.

The square root of 165641540 is about 12870.1802629178. The cubic root of 165641540 is about 549.1905890239.

The spelling of 165641540 in words is "one hundred sixty-five million, six hundred forty-one thousand, five hundred forty".