165623540 has 24 divisors (see below), whose sum is σ = 353513832. Its totient is φ = 65162880.

The previous prime is 165623527. The next prime is 165623543. The reversal of 165623540 is 45326561.

It can be written as a sum of positive squares in 4 ways, for example, as 9972964 + 155650576 = 3158^2 + 12476^2 .

It is a junction number, because it is equal to n+sod(n) for n = 165623497 and 165623506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165623543) 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, 66659 + ... + 69098.

It is an arithmetic number, because the mean of its divisors is an integer number (14729743).

Almost surely, 2^165623540 is an apocalyptic number.

165623540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165623540 is an abundant number, since it is smaller than the sum of its proper divisors (187890292).

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

165623540 is a wasteful number, since it uses less digits than its factorization.

165623540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135827 (or 135825 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 32.

The square root of 165623540 is about 12869.4809530144. The cubic root of 165623540 is about 549.1706950836.

It can be divided in two parts, 16562 and 3540, that added together give a palindrome (20102).

The spelling of 165623540 in words is "one hundred sixty-five million, six hundred twenty-three thousand, five hundred forty".