16891845180961 has 3 divisors (see below), whose sum is σ = 16891849290931. Its totient is φ = 16891841070992.

The previous prime is 16891845180953. The next prime is 16891845180989. The reversal of 16891845180961 is 16908154819861.

The square root of 16891845180961 is 4109969.

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.

It can be written as a sum of positive squares in only one way, i.e., 14216526971361 + 2675318209600 = 3770481^2 + 1635640^2 .

It is not a de Polignac number, because 16891845180961 - 2³ = 16891845180953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16891845180911) 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, 2054985 + ... + 6164953.

Almost surely, 2^{16891845180961} is an apocalyptic number.

16891845180961 is the 4109969-th square number.

16891845180961 is the 2054985-th centered octagonal number.

It is an amenable number.

16891845180961 is a deficient number, since it is larger than the sum of its proper divisors (4109970).

16891845180961 is an frugal number, since it uses more digits than its factorization.

16891845180961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8219938 (or 4109969 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 67.

The spelling of 16891845180961 in words is "sixteen trillion, eight hundred ninety-one billion, eight hundred forty-five million, one hundred eighty thousand, nine hundred sixty-one".