19491720386 has 8 divisors (see below), whose sum is σ = 29265887244. Its totient is φ = 9736424640.

The previous prime is 19491720373. The next prime is 19491720401. The reversal of 19491720386 is 68302719491.

It can be written as a sum of positive squares in 2 ways, for example, as 15281657161 + 4210063225 = 123619^2 + 64885^2 .

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

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4715195 + ... + 4719326.

Almost surely, 2^19491720386 is an apocalyptic number.

19491720386 is a deficient number, since it is larger than the sum of its proper divisors (9774166858).

19491720386 is a wasteful number, since it uses less digits than its factorization.

19491720386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9435556.

The product of its (nonzero) digits is 653184, while the sum is 50.

The spelling of 19491720386 in words is "nineteen billion, four hundred ninety-one million, seven hundred twenty thousand, three hundred eighty-six".