16521161121 has 6 divisors (see below), whose sum is σ = 23863899410. Its totient is φ = 11014107408.

The previous prime is 16521161087. The next prime is 16521161131. The reversal of 16521161121 is 12116112561.

16521161121 is a `hidden beast` number, since 1 + 6 + 5 + 21 + 1 + 611 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 15119407521 + 1401753600 = 122961^2 + 37440^2 .

It is not a de Polignac number, because 16521161121 - 2⁶ = 16521161057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16521161131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 917842276 + ... + 917842293.

Almost surely, 2^16521161121 is an apocalyptic number.

It is an amenable number.

16521161121 is a deficient number, since it is larger than the sum of its proper divisors (7342738289).

16521161121 is a wasteful number, since it uses less digits than its factorization.

16521161121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1835684575 (or 1835684572 counting only the distinct ones).

The product of its digits is 720, while the sum is 27.

Adding to 16521161121 its reverse (12116112561), we get a palindrome (28637273682).

The spelling of 16521161121 in words is "sixteen billion, five hundred twenty-one million, one hundred sixty-one thousand, one hundred twenty-one".