19662738561 has 12 divisors (see below), whose sum is σ = 28582638292. Its totient is φ = 13024997856.

The previous prime is 19662738541. The next prime is 19662738587. The reversal of 19662738561 is 16583726691.

19662738561 is a `hidden beast` number, since 1 + 9 + 6 + 6 + 2 + 73 + 8 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13521038400 + 6141700161 = 116280^2 + 78369^2 .

It is not a de Polignac number, because 19662738561 - 2¹⁵ = 19662705793 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19662738498 and 19662738507.

It is not an unprimeable number, because it can be changed into a prime (19662738541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6956386 + ... + 6959211.

Almost surely, 2^19662738561 is an apocalyptic number.

It is an amenable number.

19662738561 is a deficient number, since it is larger than the sum of its proper divisors (8919899731).

19662738561 is a wasteful number, since it uses less digits than its factorization.

19662738561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13915760 (or 13915757 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 54.

The spelling of 19662738561 in words is "nineteen billion, six hundred sixty-two million, seven hundred thirty-eight thousand, five hundred sixty-one".