19809659649 has 96 divisors (see below), whose sum is σ = 31531327488. Its totient is φ = 11007360000.

The previous prime is 19809659641. The next prime is 19809659651. The reversal of 19809659649 is 94695690891.

It is not a de Polignac number, because 19809659649 - 2³ = 19809659641 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19809659649.

It is not an unprimeable number, because it can be changed into a prime (19809659641) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 40345294 + ... + 40345784.

It is an arithmetic number, because the mean of its divisors is an integer number (328451328).

Almost surely, 2^19809659649 is an apocalyptic number.

It is an amenable number.

19809659649 is a deficient number, since it is larger than the sum of its proper divisors (11721667839).

19809659649 is a wasteful number, since it uses less digits than its factorization.

19809659649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719 (or 706 counting only the distinct ones).

The product of its (nonzero) digits is 37791360, while the sum is 66.

The spelling of 19809659649 in words is "nineteen billion, eight hundred nine million, six hundred fifty-nine thousand, six hundred forty-nine".