161801563 has 36 divisors (see below), whose sum is σ = 216240976. Its totient is φ = 118483200.

The previous prime is 161801551. The next prime is 161801569. The reversal of 161801563 is 365108161.

It is not a de Polignac number, because 161801563 - 2⁹ = 161801051 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161801569) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 244453 + ... + 245113.

Almost surely, 2^161801563 is an apocalyptic number.

161801563 is a deficient number, since it is larger than the sum of its proper divisors (54439413).

161801563 is a wasteful number, since it uses less digits than its factorization.

161801563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724 (or 696 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 161801563 is about 12720.1243311534. The cubic root of 161801563 is about 544.9135042150.

The spelling of 161801563 in words is "one hundred sixty-one million, eight hundred one thousand, five hundred sixty-three".