161853309 has 22 divisors (see below), whose sum is σ = 242867166. Its totient is φ = 107862840.

The previous prime is 161853301. The next prime is 161853319. The reversal of 161853309 is 903358161.

It is a happy number.

161853309 is a `hidden beast` number, since 1 + 618 + 5 + 3 + 30 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 124947684 + 36905625 = 11178^2 + 6075^2 .

It is not a de Polignac number, because 161853309 - 2³ = 161853301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161853301) by changing a digit.

It is a polite number, since it can be written in 21 ways as a sum of consecutive naturals, for example, 57679 + ... + 60419.

Almost surely, 2^161853309 is an apocalyptic number.

It is an amenable number.

161853309 is a deficient number, since it is larger than the sum of its proper divisors (81013857).

161853309 is an frugal number, since it uses more digits than its factorization.

161853309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2771 (or 2744 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 161853309 is about 12722.1581895526. The cubic root of 161853309 is about 544.9715878912.

The spelling of 161853309 in words is "one hundred sixty-one million, eight hundred fifty-three thousand, three hundred nine".