16129549177921 has 3 divisors (see below), whose sum is σ = 16129553194083. Its totient is φ = 16129545161760.

The previous prime is 16129549177919. The next prime is 16129549177999. The reversal of 16129549177921 is 12977194592161.

The square root of 16129549177921 is 4016161.

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., 6070502617921 + 10059046560000 = 2463839^2 + 3171600^2 .

It is not a de Polignac number, because 16129549177921 - 2¹ = 16129549177919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16129549172921) 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 2 ways as a sum of consecutive naturals, for example, 2008081 + ... + 6024241.

It is an arithmetic number, because the mean of its divisors is an integer number (5376517731361).

Almost surely, 2^{16129549177921} is an apocalyptic number.

16129549177921 is the 4016161-st square number.

16129549177921 is the 2008081-st centered octagonal number.

It is an amenable number.

16129549177921 is a deficient number, since it is larger than the sum of its proper divisors (4016162).

16129549177921 is an frugal number, since it uses more digits than its factorization.

16129549177921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8032322 (or 4016161 counting only the distinct ones).

The product of its digits is 17146080, while the sum is 64.

The spelling of 16129549177921 in words is "sixteen trillion, one hundred twenty-nine billion, five hundred forty-nine million, one hundred seventy-seven thousand, nine hundred twenty-one".