161856203 has 4 divisors (see below), whose sum is σ = 165300000. Its totient is φ = 158412408.

The previous prime is 161856199. The next prime is 161856209. The reversal of 161856203 is 302658161.

It is a happy number.

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 161856203 - 2² = 161856199 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161856203.

It is not an unprimeable number, because it can be changed into a prime (161856209) 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, 1721828 + ... + 1721921.

It is an arithmetic number, because the mean of its divisors is an integer number (41325000).

Almost surely, 2^161856203 is an apocalyptic number.

161856203 is a deficient number, since it is larger than the sum of its proper divisors (3443797).

161856203 is an equidigital number, since it uses as much as digits as its factorization.

161856203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3443796.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 161856203 is about 12722.2719276079. The cubic root of 161856203 is about 544.9748359731.

The spelling of 161856203 in words is "one hundred sixty-one million, eight hundred fifty-six thousand, two hundred three".