16533778336661 has 4 divisors (see below), whose sum is σ = 16544054148300. Its totient is φ = 16523502525024.

The previous prime is 16533778336633. The next prime is 16533778336681. The reversal of 16533778336661 is 16663387733561.

16533778336661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 8569050162436 + 7964728174225 = 2927294^2 + 2822185^2 .

It is a cyclic number.

It is not a de Polignac number, because 16533778336661 - 2⁶ = 16533778336597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16533778336681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5137903406 + ... + 5137906623.

It is an arithmetic number, because the mean of its divisors is an integer number (4136013537075).

Almost surely, 2^{16533778336661} is an apocalyptic number.

It is an amenable number.

16533778336661 is a deficient number, since it is larger than the sum of its proper divisors (10275811639).

16533778336661 is a wasteful number, since it uses less digits than its factorization.

16533778336661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10275811638.

The product of its digits is 205752960, while the sum is 65.

The spelling of 16533778336661 in words is "sixteen trillion, five hundred thirty-three billion, seven hundred seventy-eight million, three hundred thirty-six thousand, six hundred sixty-one".