161311164521 has 16 divisors (see below), whose sum is σ = 180748910160. Its totient is φ = 142936953600.

The previous prime is 161311164503. The next prime is 161311164551. The reversal of 161311164521 is 125461113161.

It can be written as a sum of positive squares in 8 ways, for example, as 8183735296 + 153127429225 = 90464^2 + 391315^2 .

It is a cyclic number.

It is not a de Polignac number, because 161311164521 - 2¹⁴ = 161311148137 is a prime.

It is a super-2 number, since 2×161311164521² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161311164551) 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 15 ways as a sum of consecutive naturals, for example, 1171430 + ... + 1301871.

It is an arithmetic number, because the mean of its divisors is an integer number (11296806885).

Almost surely, 2^161311164521 is an apocalyptic number.

It is an amenable number.

161311164521 is a deficient number, since it is larger than the sum of its proper divisors (19437745639).

161311164521 is a wasteful number, since it uses less digits than its factorization.

161311164521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2473516.

The product of its digits is 4320, while the sum is 32.

Adding to 161311164521 its reverse (125461113161), we get a palindrome (286772277682).

The spelling of 161311164521 in words is "one hundred sixty-one billion, three hundred eleven million, one hundred sixty-four thousand, five hundred twenty-one".