19661241599 has 4 divisors (see below), whose sum is σ = 19664883264. Its totient is φ = 19657599936.

The previous prime is 19661241571. The next prime is 19661241601. The reversal of 19661241599 is 99514216691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99514216691 = 79 ⋅1259673629.

It is a cyclic number.

It is not a de Polignac number, because 19661241599 - 2⁸ = 19661241343 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19661241599.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19661241799) 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, 1812722 + ... + 1823535.

It is an arithmetic number, because the mean of its divisors is an integer number (4916220816).

Almost surely, 2^19661241599 is an apocalyptic number.

19661241599 is a deficient number, since it is larger than the sum of its proper divisors (3641665).

19661241599 is an equidigital number, since it uses as much as digits as its factorization.

19661241599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3641664.

The product of its digits is 1049760, while the sum is 53.

The spelling of 19661241599 in words is "nineteen billion, six hundred sixty-one million, two hundred forty-one thousand, five hundred ninety-nine".