161856863 has 4 divisors (see below), whose sum is σ = 184979280. Its totient is φ = 138734448.

The previous prime is 161856857. The next prime is 161856887. The reversal of 161856863 is 368658161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 368658161 = 79 ⋅4666559.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161856863 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 (161856803) 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, 11561198 + ... + 11561211.

It is an arithmetic number, because the mean of its divisors is an integer number (46244820).

Almost surely, 2^161856863 is an apocalyptic number.

161856863 is a deficient number, since it is larger than the sum of its proper divisors (23122417).

161856863 is an equidigital number, since it uses as much as digits as its factorization.

161856863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23122416.

The product of its digits is 207360, while the sum is 44.

The square root of 161856863 is about 12722.2978663447. The cubic root of 161856863 is about 544.9755767188.

The spelling of 161856863 in words is "one hundred sixty-one million, eight hundred fifty-six thousand, eight hundred sixty-three".