161865547 has 4 divisors (see below), whose sum is σ = 162801360. Its totient is φ = 160929736.

The previous prime is 161865523. The next prime is 161865553. The reversal of 161865547 is 745568161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161865547 - 2⁷ = 161865419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161865647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 467647 + ... + 467992.

It is an arithmetic number, because the mean of its divisors is an integer number (40700340).

Almost surely, 2^161865547 is an apocalyptic number.

161865547 is a deficient number, since it is larger than the sum of its proper divisors (935813).

161865547 is an equidigital number, since it uses as much as digits as its factorization.

161865547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935812.

The product of its digits is 201600, while the sum is 43.

The square root of 161865547 is about 12722.6391523143. The cubic root of 161865547 is about 544.9853229501.

The spelling of 161865547 in words is "one hundred sixty-one million, eight hundred sixty-five thousand, five hundred forty-seven".