161121506517 has 6 divisors (see below), whose sum is σ = 232731064982. Its totient is φ = 107414337672.

The previous prime is 161121506501. The next prime is 161121506519. The reversal of 161121506517 is 715605121161.

161121506517 is a `hidden beast` number, since 1 + 611 + 21 + 5 + 0 + 6 + 5 + 17 = 666.

It can be written as a sum of positive squares in only one way, i.e., 120482575236 + 40638931281 = 347106^2 + 201591^2 .

It is not a de Polignac number, because 161121506517 - 2⁴ = 161121506501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161121506519) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8951194798 + ... + 8951194815.

Almost surely, 2^161121506517 is an apocalyptic number.

It is an amenable number.

161121506517 is a deficient number, since it is larger than the sum of its proper divisors (71609558465).

161121506517 is a wasteful number, since it uses less digits than its factorization.

161121506517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17902389619 (or 17902389616 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 36.

Adding to 161121506517 its reverse (715605121161), we get a palindrome (876726627678).

The spelling of 161121506517 in words is "one hundred sixty-one billion, one hundred twenty-one million, five hundred six thousand, five hundred seventeen".