19945391608 has 8 divisors (see below), whose sum is σ = 37397609280. Its totient is φ = 9972695800.

The previous prime is 19945391581. The next prime is 19945391629. The reversal of 19945391608 is 80619354991.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1246586968 + ... + 1246586983.

It is an arithmetic number, because the mean of its divisors is an integer number (4674701160).

Almost surely, 2^19945391608 is an apocalyptic number.

It is an amenable number.

19945391608 is a deficient number, since it is larger than the sum of its proper divisors (17452217672).

19945391608 is a wasteful number, since it uses less digits than its factorization.

19945391608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2493173957 (or 2493173953 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 19945391608 in words is "nineteen billion, nine hundred forty-five million, three hundred ninety-one thousand, six hundred eight".