161243521 has 8 divisors (see below), whose sum is σ = 175343400. Its totient is φ = 147656448.

The previous prime is 161243491. The next prime is 161243527. The reversal of 161243521 is 125342161.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 90935296 + 70308225 = 9536^2 + 8385^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161243521 - 2¹¹ = 161241473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161243527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 127546 + ... + 128803.

It is an arithmetic number, because the mean of its divisors is an integer number (21917925).

Almost surely, 2^161243521 is an apocalyptic number.

It is an amenable number.

161243521 is a deficient number, since it is larger than the sum of its proper divisors (14099879).

161243521 is a wasteful number, since it uses less digits than its factorization.

161243521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256403.

The product of its digits is 1440, while the sum is 25.

The square root of 161243521 is about 12698.1699862618. The cubic root of 161243521 is about 544.2863267511.

Adding to 161243521 its reverse (125342161), we get a palindrome (286585682).

The spelling of 161243521 in words is "one hundred sixty-one million, two hundred forty-three thousand, five hundred twenty-one".