19859391994 has 8 divisors (see below), whose sum is σ = 32080556340. Its totient is φ = 9165873216.

The previous prime is 19859391973. The next prime is 19859391997. The reversal of 19859391994 is 49919395891.

It can be written as a sum of positive squares in 2 ways, for example, as 19167018025 + 692373969 = 138445^2 + 26313^2 .

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 (19859391997) 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, 381911359 + ... + 381911410.

Almost surely, 2^19859391994 is an apocalyptic number.

19859391994 is a deficient number, since it is larger than the sum of its proper divisors (12221164346).

19859391994 is a wasteful number, since it uses less digits than its factorization.

19859391994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763822784.

The product of its digits is 28343520, while the sum is 67.

The spelling of 19859391994 in words is "nineteen billion, eight hundred fifty-nine million, three hundred ninety-one thousand, nine hundred ninety-four".