163331561 has 4 divisors (see below), whose sum is σ = 163357572. Its totient is φ = 163305552.

The previous prime is 163331557. The next prime is 163331569. The reversal of 163331561 is 165133361.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 65934400 + 97397161 = 8120^2 + 9869^2 .

It is a cyclic number.

It is not a de Polignac number, because 163331561 - 2² = 163331557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (163331569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2891 + ... + 18303.

It is an arithmetic number, because the mean of its divisors is an integer number (40839393).

Almost surely, 2^163331561 is an apocalyptic number.

It is an amenable number.

163331561 is a deficient number, since it is larger than the sum of its proper divisors (26011).

163331561 is a wasteful number, since it uses less digits than its factorization.

163331561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26010.

The product of its digits is 4860, while the sum is 29.

The square root of 163331561 is about 12780.1236691982. The cubic root of 163331561 is about 546.6256887702.

The spelling of 163331561 in words is "one hundred sixty-three million, three hundred thirty-one thousand, five hundred sixty-one".