161904865 has 8 divisors (see below), whose sum is σ = 195769728. Its totient is φ = 128534640.

The previous prime is 161904839. The next prime is 161904881. The reversal of 161904865 is 568409161.

161904865 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 161904865 - 2¹¹ = 161902817 is a prime.

It is a Duffinian number.

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, 122937 + ... + 124246.

It is an arithmetic number, because the mean of its divisors is an integer number (24471216).

Almost surely, 2^161904865 is an apocalyptic number.

It is an amenable number.

161904865 is a deficient number, since it is larger than the sum of its proper divisors (33864863).

161904865 is a wasteful number, since it uses less digits than its factorization.

161904865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247319.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 161904865 is about 12724.1842567608. The cubic root of 161904865 is about 545.0294459864.

The spelling of 161904865 in words is "one hundred sixty-one million, nine hundred four thousand, eight hundred sixty-five".