161755549 has 4 divisors (see below), whose sum is σ = 161926236. Its totient is φ = 161584864.

The previous prime is 161755547. The next prime is 161755571. The reversal of 161755549 is 945557161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 945557161 = 4517 ⋅209333.

It can be written as a sum of positive squares in 2 ways, for example, as 32205625 + 129549924 = 5675^2 + 11382^2 .

It is a cyclic number.

It is not a de Polignac number, because 161755549 - 2¹ = 161755547 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161755541) 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 3 ways as a sum of consecutive naturals, for example, 83914 + ... + 85819.

It is an arithmetic number, because the mean of its divisors is an integer number (40481559).

Almost surely, 2^161755549 is an apocalyptic number.

It is an amenable number.

161755549 is a deficient number, since it is larger than the sum of its proper divisors (170687).

161755549 is an equidigital number, since it uses as much as digits as its factorization.

161755549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170686.

The product of its digits is 189000, while the sum is 43.

The square root of 161755549 is about 12718.3154938066. The cubic root of 161755549 is about 544.8618441717.

The spelling of 161755549 in words is "one hundred sixty-one million, seven hundred fifty-five thousand, five hundred forty-nine".