161884865 has 4 divisors (see below), whose sum is σ = 194261844. Its totient is φ = 129507888.

The previous prime is 161884847. The next prime is 161884867. The reversal of 161884865 is 568488161.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21864976 + 140019889 = 4676^2 + 11833^2 .

It is a cyclic number.

It is not a de Polignac number, because 161884865 - 2¹² = 161880769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161884867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16188482 + ... + 16188491.

It is an arithmetic number, because the mean of its divisors is an integer number (48565461).

Almost surely, 2^161884865 is an apocalyptic number.

It is an amenable number.

161884865 is a deficient number, since it is larger than the sum of its proper divisors (32376979).

161884865 is an equidigital number, since it uses as much as digits as its factorization.

161884865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32376978.

The product of its digits is 368640, while the sum is 47.

The square root of 161884865 is about 12723.3983274910. The cubic root of 161884865 is about 545.0070026876.

It can be divided in two parts, 16 and 1884865, that added together give a palindrome (1884881).

The spelling of 161884865 in words is "one hundred sixty-one million, eight hundred eighty-four thousand, eight hundred sixty-five".