16681144385 has 4 divisors (see below), whose sum is σ = 20017373268. Its totient is φ = 13344915504.

The previous prime is 16681144351. The next prime is 16681144397. The reversal of 16681144385 is 58344118661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4215645184 + 12465499201 = 64928^2 + 111649^2 .

It is a cyclic number.

It is not a de Polignac number, because 16681144385 - 2¹⁰ = 16681143361 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1668114434 + ... + 1668114443.

It is an arithmetic number, because the mean of its divisors is an integer number (5004343317).

Almost surely, 2^16681144385 is an apocalyptic number.

It is an amenable number.

16681144385 is a deficient number, since it is larger than the sum of its proper divisors (3336228883).

16681144385 is an equidigital number, since it uses as much as digits as its factorization.

16681144385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3336228882.

The product of its digits is 552960, while the sum is 47.

The spelling of 16681144385 in words is "sixteen billion, six hundred eighty-one million, one hundred forty-four thousand, three hundred eighty-five".