161975865 has 16 divisors (see below), whose sum is σ = 264676608. Its totient is φ = 84548736.

The previous prime is 161975839. The next prime is 161975873. The reversal of 161975865 is 568579161.

It is not a de Polignac number, because 161975865 - 2¹¹ = 161973817 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114172 + ... + 115581.

It is an arithmetic number, because the mean of its divisors is an integer number (16542288).

Almost surely, 2^161975865 is an apocalyptic number.

161975865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161975865 is a deficient number, since it is larger than the sum of its proper divisors (102700743).

161975865 is a wasteful number, since it uses less digits than its factorization.

161975865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229808.

The product of its digits is 453600, while the sum is 48.

The square root of 161975865 is about 12726.9739137000. The cubic root of 161975865 is about 545.1091047733.

The spelling of 161975865 in words is "one hundred sixty-one million, nine hundred seventy-five thousand, eight hundred sixty-five".