16566697394 has 8 divisors (see below), whose sum is σ = 26761588140. Its totient is φ = 7646168016.

The previous prime is 16566697391. The next prime is 16566697451. The reversal of 16566697394 is 49379666561.

It can be written as a sum of positive squares in 2 ways, for example, as 13837993225 + 2728704169 = 117635^2 + 52237^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (16566697391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 318590309 + ... + 318590360.

Almost surely, 2^16566697394 is an apocalyptic number.

16566697394 is a deficient number, since it is larger than the sum of its proper divisors (10194890746).

16566697394 is a wasteful number, since it uses less digits than its factorization.

16566697394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637180684.

The product of its digits is 44089920, while the sum is 62.

The spelling of 16566697394 in words is "sixteen billion, five hundred sixty-six million, six hundred ninety-seven thousand, three hundred ninety-four".