165561396 has 216 divisors, whose sum is σ = 534915360. Its totient is φ = 39473280.

The previous prime is 165561379. The next prime is 165561397. The reversal of 165561396 is 693165561.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165561397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 924835 + ... + 925013.

It is an arithmetic number, because the mean of its divisors is an integer number (2476460).

Almost surely, 2^165561396 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165561396, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267457680).

165561396 is an abundant number, since it is smaller than the sum of its proper divisors (369353964).

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

165561396 is a wasteful number, since it uses less digits than its factorization.

165561396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235 (or 215 counting only the distinct ones).

The product of its digits is 145800, while the sum is 42.

The square root of 165561396 is about 12867.0663323075. The cubic root of 165561396 is about 549.1020012797.

The spelling of 165561396 in words is "one hundred sixty-five million, five hundred sixty-one thousand, three hundred ninety-six".