161020356521 has 16 divisors (see below), whose sum is σ = 164224051200. Its totient is φ = 157849388928.

The previous prime is 161020356487. The next prime is 161020356631. The reversal of 161020356521 is 125653020161.

It is a cyclic number.

It is not a de Polignac number, because 161020356521 - 2¹⁸ = 161020094377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161020356121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20217086 + ... + 20225048.

It is an arithmetic number, because the mean of its divisors is an integer number (10264003200).

Almost surely, 2^161020356521 is an apocalyptic number.

It is an amenable number.

161020356521 is a deficient number, since it is larger than the sum of its proper divisors (3203694679).

161020356521 is a wasteful number, since it uses less digits than its factorization.

161020356521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9968.

The product of its (nonzero) digits is 10800, while the sum is 32.

Adding to 161020356521 its reverse (125653020161), we get a palindrome (286673376682).

The spelling of 161020356521 in words is "one hundred sixty-one billion, twenty million, three hundred fifty-six thousand, five hundred twenty-one".