161050518721 has 3 divisors (see below), whose sum is σ = 161050920033. Its totient is φ = 161050117410.

The previous prime is 161050518637. The next prime is 161050518773. The reversal of 161050518721 is 127815050161.

The square root of 161050518721 is 401311.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 127815050161 = 43 ⋅2972443027.

It is not a de Polignac number, because 161050518721 - 2³⁷ = 23611565249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161050518791) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 200656 + ... + 601966.

It is an arithmetic number, because the mean of its divisors is an integer number (53683640011).

Almost surely, 2^161050518721 is an apocalyptic number.

161050518721 is the 401311-st square number.

161050518721 is the 200656-th centered octagonal number.

It is an amenable number.

161050518721 is a deficient number, since it is larger than the sum of its proper divisors (401312).

161050518721 is an frugal number, since it uses more digits than its factorization.

161050518721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802622 (or 401311 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 37.

Adding to 161050518721 its reverse (127815050161), we get a palindrome (288865568882).

The spelling of 161050518721 in words is "one hundred sixty-one billion, fifty million, five hundred eighteen thousand, seven hundred twenty-one".