161540305 has 8 divisors (see below), whose sum is σ = 193955112. Its totient is φ = 129161088.

The previous prime is 161540297. The next prime is 161540329. The reversal of 161540305 is 503045161.

It can be written as a sum of positive squares in 4 ways, for example, as 47114496 + 114425809 = 6864^2 + 10697^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161540305 - 2³ = 161540297 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161540305.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2397 + ... + 18133.

It is an arithmetic number, because the mean of its divisors is an integer number (24244389).

Almost surely, 2^161540305 is an apocalyptic number.

It is an amenable number.

161540305 is a deficient number, since it is larger than the sum of its proper divisors (32414807).

161540305 is a wasteful number, since it uses less digits than its factorization.

161540305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17795.

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

The square root of 161540305 is about 12709.8507072271. The cubic root of 161540305 is about 544.6200589559.

Adding to 161540305 its reverse (503045161), we get a palindrome (664585466).

The spelling of 161540305 in words is "one hundred sixty-one million, five hundred forty thousand, three hundred five".